Tulips for the desert?

Spring bulb planting time is on across North America!  Many types of bulbs do well in desert and xeric gardens: hyacinths, ranunculus, iris, narcissus, crocus, alliums can all be happy. One bulb that’s often left off the list are tulips. Why is that?

The tall flashy hybrid or Darwinian tulips that fill the catalog photos are usually considered an annual in most desert gardens. They require more chilling than the our desert winters can usually provide and can be a little fussy about soil and water.
But tulips can be very happy in xeriscapes. In fact they can get so happy they’ll set seed and naturalize in the right conditions. And which tulips are those you ask? (Yes you did, I heard you.)
They’re species tulips and are non-hybridized. They’re more of “wild” type of plant. What’s so special about them?
They’re tough, amazingly tough.

Tulips are originally from mountainous areas of the Mediterranean, Middle East and Asia. Some are also native to Southern Europe, North Africa, and several Mediterranean islands. They’re frequently found clinging to barren mountain ledges, rocky areas exposed to wind and cold, and drought ridden slopes.

Map by Tulips in the Wild
For an interactive format with species information go here:
https://www.tulipsinthewild.com/map_table/tulip_origin_map.html

Species tulips are shorter and smaller than hybrids but what they lack in stature they more than make up for in resilience and showy display. They’re an early bloomer in the desert southwest which is wonderful for the pollinators that are often active on warm winter and early spring days.

Their foliage is usually more varied than hybrids; some have broad, curled edged leaves, some are tall and narrow. The color varies too, from a bluish tint to shades of green. Some varieties even have multiple blooms per stem.

Many species are attractive whether the blooms are closed or opened. They often have very different coloration inside and out.

Closed…
…and open

Some have contrasting pollen color which adds great visual interest.

These have a deep purple pollen.

Species tulips are usually perennial in warm winter climates. They increase via bulb offsets while many will set seed. They aren’t fussy about soil as long as it’s well drained. But like all plants they do require water during bloom and while the leaves are green but still, not as much as other bulbs. They’re perfect for xeriscaped or low water landscapes since they require less overall water than other bulbs. Plus, they prefer to be dry during their dormant season, which is summer to fall.

These tough little beauties can occasionally be found in garden centers but for the best selection shop online, search for “species tulips.” Do some homework first, and become familiar with the the available varieties.

Plant these tulips from fall to early winter. Provide full sun and good drainage, rocky or lean sandy soils are ideal and most closely approximate their native conditions.

Don’t overplant with species that require a lot of summer water. Mix these bulbs with other plants that prefer hot dry conditions. Tuck them into those corners that get spring – early summer sunshine, spots that don’t get much summer water, or put in containers that you can enjoy and then ignore during the summer. Pot them in cactus mix combined with a small amount of regular potting soil and top with an organic mulch. Remember, drainage is a must and overly rich or high organic matter conditions aren’t to their liking.

If you live in a dry or desert region and have never tried species tulips, why not give them chance. You might just discover a new favorite.

Predicting hurricane tracks and what they leave behind

In my last blog post in late August, the Atlantic tropical season was just beginning to wake from a long nap, with several areas of interest appearing on the National Hurricane Center’s (NHC) map. Since that time, the season has become incredibly active, with Hurricanes Fiona and Ian causing tremendous damage in North America. Other parts of the world have also seen damaging storms, including Hurricane Kay in the Eastern Pacific, post-typhoon Merbok in Alaska, and Typhoons Hinnamnor in South Korea, Nanmadol in Japan, and Noru in the Philippines. So, with apologies to those who live far from hurricane parts of the world, I want to talk one more time about tropical systems.

Heavy rain. Source: Faldrian, Commons Wikimedia

Where do we stand with the tropical season now?

As I am writing this on Thursday morning, September 29, I hear the sound of Ian’s wind in the tulip poplar trees outside my house in Athens, GA. Ian is still in central Florida, just about to come off the coast into the Atlantic Ocean, so that gives you an idea of how far the influence of a tropical storm can spread, especially with a strong high-pressure center to our north that is increasing the pressure gradient driving the winds. Ian made landfall yesterday afternoon near Fort Myers, Florida, as an almost-category 5 storm, with winds of 150 mph (some reports say 155 mph). The videos I saw yesterday showed the power of the storm, with tremendous wind gusts and a storm surge that surpassed 10 feet in some places. I know the damage is horrific, and some of those areas will never recover completely from the storm, as buildings have been washed away and even shorelines may have changed due to the force of the wind and water. Since Ian is expected to curve back toward the East Coast on Friday and may strengthen again, its effects are not over yet. Fortunately, a weaker storm has lower impacts, but folks along the Georgia and South Carolina coasts will be feeling those impacts in the next few days before Ian moves out of the area and dissipates.

Hurricane Ian, September 27, 2002.

Hurricane Fiona lashed Puerto Rico and the Dominican Republic with rain of up to two feet in some places around September 18-19 before moving rapidly to the north and slamming into Nova Scotia as a post-tropical cyclone on September 24. It caused tremendous damage in both places from storm surge, wind, and rains. The floods in Puerto Rico destroyed a lot of local farms and gardens in the southern half of the islands where the rain was heaviest and in doing so, eliminated an important source of locally produced food as well as disabling a fragile power grid that had not yet recovered from Hurricane Maria in 2017. The storms in other parts of the world have had similarly bad effects on the lands over which they moved, with loss of trees and buildings and high storm surges wiping out coastal infrastructure. Not all hurricane impacts are bad, however, since the rain from Hurricane Kay in southern California helped reduce drought conditions there in a time when not much rain usually falls in that part of the world.

Predicting the tracks of hurricanes

One of the questions that have arisen with Hurricane Ian has been the prediction of where the hurricane would go. Predicting the track of a hurricane is an art that includes the use of multiple computer models that simulate conditions over the life of the storm. That includes sea surface temperature, vertical atmospheric structure, and the surrounding wind field which will push the storm around. On the news you will often see maps that show all the individual model results on one map, which ends up looking like a mass of spaghetti noodles, hence the term “spaghetti models”.

Ensemble of Hurricane Ian forecasts from the GEFS model issued on September 26, 2022. Source: WeatherNerds.org

Forecasters look at all the individual model tracks together to see how consistent they are with each other and where the differences lie. Then the human forecasters use their knowledge of how well those models behave under different weather conditions to create a “forecast cone” that shows the region where the center of the storm is likely to go.

No one model is right all the time because they weigh different weather factors differently. In the case of Ian, the models run by European weather services did better, but that is not always the case. Generally, they say that 2/3rd of the time, the central low pressure will stay within the predicted cone, although the storm itself is usually much larger than the cone and hazards like high wind, heavy rain, tornadoes, and storm surge can and do occur far outside the cone. If there is a lot of spread in the models, then the forecast cone is wider, indicating that they are less certain about where the storm will go.

The models are run every six hours or so, and each time the cone is updated to include model results that include new weather data observed since the last forecast was issued. As this happens, people that are in or near the cone must respond to the forecast by deciding whether to evacuate or stay in place and where to go if they do leave, since they don’t want to evacuate to a location that could be hit by the storm if the cone shifts. When the forecast is especially tricky, as it was with Ian, the movement of the cone over time can become overwhelming to people who just want to find a place they will be safe. The forecasts of where the storm is likely to travel are improving over time, but the tracks will never be 100% accurate because the atmosphere is a complicated place that we can’t simulate perfectly using even the best computers, so confusion is likely to continue to occur in future storms.

Downed trees and powerlines in Bartow, FL, following Hurricane Ian. Source: State Farm, Commons Wikimedia.

Dealing with flooded gardens

Since this is a blog about gardening, I want to end up mentioning what impacts these storms have on gardens. Coastal areas where there is a storm surge will see inches to feet of seawater flow over their land. The water contains salt but can also contain toxic chemicals from boats and tanks that are damaged by floating debris or strong waves. The salt and chemicals can kill garden plants but also may get deposited in the soil as the water sinks in, leaving toxic residue behind. The physical motion of the water on and off the land can also scour the topsoil and change the soil structure or deposit sand on top. Saturated soils can drown the plants by keeping oxygen from reaching the roots of plants. And of course, the howling winds can snap the plants, bushes, and trees above the ground, leading to damage that can be taken advantage of by pests and diseases. In areas where there is heavy rain and freshwater flooding, salt is not usually a problem, but all the other problems with too much water can occur there, too. For those who live where storm damage is heaviest, helping their gardens to recover will be a long process even if their houses survive the storm.

Hurricane Ian clouds at sunset. Source: Jason Mallard.

The Atlantic tropical season is not over yet for us in the Southeast, but I know that in other parts of the United States and the world, the seasons march on, so in the next months I will move on to talk about fall frosts and the upcoming winter. Thanks for bearing with me as I explore tropical storm systems. Please keep all of those affected by our storms this year in your thoughts and prayers as they work to recover from damage and disaster.

Irrigation bags: the good (rarely), the bad (frequently) and the ugly (all of them)

Irrigation bags, often called “tree gators,” are durable plastic bags used for irrigating newly planted trees. These projects have been discussed here and here and I still don’t like them as they don’t consistently benefit trees and often create conditions conducive to pests and disease. Plus, as the blog title suggests, their aesthetic attributes are nonexistent.

Surprisingly, camoflauge green doesn’t actually camoflauge anything.

Newly installed trees and shrubs generally need to have supplemental water, period. It doesn’t matter if they are “drought tolerant” species – any plant needs sufficient water to establish roots. And where automated irrigation systems aren’t possible, there are many products that promise to deliver water to the establishing root system. Unfortunately, they often deliver other things as well, including pests, disease, and early death.

To be fair, many time these trees die because they were poorly planted: we know that improperly amended soils, structurally compromised root systems, inadequate root preparation, and/or poor installation are the leading causes of young tree failure. But anything that covers the trunks of young trees and reduces air flow and light exposure will, over time, create a dark, moist, and reduced oxygen environment that’s damaging to the bark of young trees. Wet, damaged bark allows opportunistic pests and pathogens to invade.

Until a few weeks ago, I had not seen any irrigation bags that I actually thought might work. These bags are installed on stakes away from the tree trunks, and they deliver water to the area where tree roots need to grow, enhancing root establishment. It took a trip to Malmö, Sweden to see this innovative approach and my immediate reaction was “why hasn’t anyone thought of this before?”

There are many types of irrigation bags, from sleeves to donuts, but none of them are as good for tree or soil health as a thick layer of arborist wood chips. When wood chips can’t be used for some reason, irrigation bags set well away from the tree and actually kept full of water might be a good solution.

Arborist wood chips provide a highly absorbant matrix that releases water slowly into the root zone.

What the words on the seed packet or food label mean…

This article was originally published (surprisingly?) by the Mother Earth News Blog.

What do the words on your food (or garden supplies) labels mean? Do you know the difference between organic, natural, and sustainable? Are there rules about who can use which labels? When you are shopping at the farmers market or grocery store, or when you’re buying seeds or plants at the garden center, it is important to know what the words used to describe the product mean. It is also important to understand that some words have different meanings to different people and sometimes are used more for marketing (and sometimes misleading customers) than conveying actual meaning. Let’s take a look at some of the words that have an “official” definition, some where the meaning can be interpreted differently, and some that can be misleading or misinterpreted.

“Official” words for foods and plants

There are a handful of words that you’ll find at the grocery store, farmers market, or garden center that have an official definition because they are either part of a law or code or are part of an official certification process.

USDA Organic | USDA

For example, in the US for a product to bear the term “certified organic” or “organic“, it must be produced in accordance with the National Organic Program organic certification process outlined in federal policy/law and administered by the USDA. While there are many minute details for organic production, the “big picture” definition is that only organic/naturally occurring soil amendments and pesticides can be used – typically from a biological or elemental source. It is important to note that organic does not mean pesticide free. Repeat: ORGANIC DOES NOT MEAN PESTICIDE FREE

The organic certification process can be costly and time consuming, and some producers feel that restrictions do not go far enough, so alternative certifications have been developed such as Certified Naturally Grown and Regenerative Organic Certified. These certifications are not administered by the USDA, but rather by individual organizations that have developed them.

Another term that has emerged is “biodynamic,” which marries some organic principles with the requirement that the farm be a “closed system”, meaning that outside inputs like fertility are not used. Biodynamic production also requires the use of “preparations” that would be described as mystical or homeopathic and must be practices in accordance with “energies” such as the phase of the moon. In order to be labeled “biodynamic” a product must be certified by Demeter USA. Our very own LCS has addresses the “pseudoscience” of biodynamic growing in a previous paper. As a science-based group, we consider biodynamic to mainly be WOO.

A number of other certifications exist, such as Certified Animal Welfare Approved and Salmon Safe that guarantee things like best practices in livestock welfare and proper wild fishing practices.

“Unofficial” words for growing and marketing

While “official” words have certifications that standardize their meaning across industries, other words we use for production and marketing don’t have official meanings and are often up for interpretation. In instances where a relationship exists between a consumer and producer, say a customer buying directly from a farmer at the farmers market, a conversation can take place to share the meaning of what the words mean. In situations like a product at the grocery store, words are often left to the interpretation of the customer.

For example, while the term “organic” or “certified organic” requires official certification, using the term “organically grown” does not. Many small farmers will use this term to reflect their use of organic practices, but their understanding of practices may deviate from the “official” definition. The term natural or naturally grown may also be used to describe produce or products at the grocery store but no officially sanctioned definition exists. When customers and growers/producers can discuss what the terms mean, an understanding can be developed. However, when such a relationship doesn’t exist, it is hard to know what the terms mean. For example, an ad might say that a product is “natural, so you know that it’s good” to which I might joke that poison ivy and rattlesnake venom are both natural, but that doesn’t mean it is good for you.

The term “local” also doesn’t have a specific definition and can vary widely depending on the context. At farmers markets, it is up to the organization operating the farmers market to create vendor rules and decide what makes sense for each individual market, according to the national Farmers Market Coalition. For example, the closest meat producer may be farther outside of the city than the closest produce farmer. Markets in urban areas may need to recruit vendors from a bit farther away than those in the suburbs. If you have questions about the rules of your local market or where a vendor is farming – just ask! At a grocery store, local can mean whatever the chain wants to decide. Sometimes this can mean in the same state or other times it is regional. Often food at the grocery store will have a label saying the town or region it came from for you to learn more about each specific item.

Walmart's locally grown produce | In Oct. 2010, Walmart comm… | Flickr
Is it “local”? Depends on who you ask.

The terms sustainable and regenerative might be used to describe production practices or a farmer’s philosophy on production. While there aren’t official definitions, the USDA Sustainable Agriculture Research and Education program defines sustainable agriculture as holistic farming practices that balances environmental stewardship, profitability, and personal/social benefit. Though most use of the term sustainable for marketing focuses on the environmental aspect. Regenerative agriculture is a relatively new philosophy of production practices that focus on environmental stewardship to reverse climate change and/or environmental degradation and social fairness and often involves improving soil health. While the terms sustainable and regenerative might seem interchangeable, there are differences (mainly around economic sustainability and around maintaining current environmental conditions vs. improving them). We’ll see how the “regenerative” term plays out – as many consider it to be a “buzzword” in some ag circles.

Words that can confuse or mislead

While there are words that may seem abundantly clear to the person using them, the information or intent may seem totally different to the audience. These words are often used as buzzwords for marketing or may be used to create a sense of fear that is misunderstood. For these words, alternative words or further explanation might reduce confusion.

One such word that is often used is chemical-free. This is often used to describe produce or food that is produced without pesticides. However, use of chemical-free can be misinterpreted and misunderstood. It may be a facetious response, but as a scientist I often cringe when I hear this word used at the farmers market because that I know that everything is made of chemicals – all rocks, plants, animals, humans, and even air and water – are chemicals. Some say that the use of this term is based in fear of pesticides (even organic ones) or is based in anti-science “chemophobia” rhetoric. Using a more precise term, such as pesticide-free conveys the same message without anti-science connotations and reduces the chance of misinterpretation.

Non-GMO is also another term that was created as a fear-based marketing term that has become pervasive at the grocery store, the seed rack, and the farmers market. While there are concerns AND benefits to genetic engineering technology, use of the term non-GMO is often redundant and confusing to consumers because, as it turns out, there are very few opportunities for gardeners, farmers, or consumers to interact with bioengineered crops. Most bioengineered crops are those that are produced as commodities – field corn, soybeans, sugar beets, cotton, canola, etc. Only a handful of crops are those that you’d find at the farmers market or produce section – sweet corn, summer squash, papaya, and one apple cultivar. But these crops are grown in very small amounts, are not available to small-scale farmers or home gardeners, are sold only in larger quantities, and require a contract for purchase. Most produce items grown in the US do not currently have a genetically engineered counterpart – there are no GMO lettuces, radishes, etc. So labeling a tomato as non-GMO is redundant and has unfortunately caused so much confusion and fear amongst consumers that many specifically demand or seek non-GMO tomatoes, even though all tomatoes are non-GMO. There is a third-party certification process through the Non-GMO Project (they’re the ones you see with the butterfly logo on almost every product, even bottled water and salt), however given the confusion and misinformation around the term, the US government recently created a standard “Bioengineered” labeling requirement for all produce and products that consist of or contain genetically engineered crops or ingredients.

A few more words on words…

While words can inform and confuse, being an educated consumer (or producer) can help reduce confusion and help us understand the food that we eat. While we haven’t covered every word you might encounter on a label here, researching words you see can help build your label vocabulary. Building interest in learning about where your food comes from should be a fun way to connect with what is on your plate and who is in your community. Go out there and enjoy the learning process! You can check out some more words related to agriculture and food here.

This article by John Porter was written as part of a partnership in collaboration with staff at the Farmers Market Coalition (FMC) as part of FMC’s partnership with Mother Earth News Fair.



More about seed packet lingo here.

The 2022 Tropical Season: It’s Alive!

In my last blog post in early August, I noted how quiet the Atlantic tropical season has been so far this year. In fact, the period from early July through this week has been one of the quietest on record, with no named storms since the short-lived Tropical Storm Colin formed along the South Carolina coast and dissipated less than 24 hours later on July 3 in eastern North Carolina. The last time we had so few named storms was 40 years ago, so while it is not unprecedented, it is certainly unusual. And we are definitely later than the average date for the first hurricane of the year. By comparison, in 1992, a strong El Niño year, Hurricane Andrew (an “A” storm, so the first of the year) had formed and taken its devastating track through southern Florida and Louisiana by this date.

Atlantic 5-day outlook on 8-28-2022

All of that is about to change, and hurricane forecasters are relieved after predicting a season of above-normal activity based on warm ocean temperatures and the current strong La Niña. They could still be correct. The National Hurricane Center’s 5-day map (as of 8-28-2022) is now showing four areas of potential development, with one area that has a 50% chance of development into a tropical depression within the next 5 days. Just in time for the peak of the season, according to the timeline we discussed earlier this month.

Why have the tropics been so quiet?

What caused the very quiet period in July and August? Hurricane climatologists point to several factors: the continuing clouds of dust that have blown off Africa and across the Atlantic Ocean towards the west, dry air moving in from Europe, which is experiencing its worst drought in 500 years, and the lack of strong waves moving off of Africa to act as seeds for tropical storm development. But the presence of warm sea surface temperatures and the lack of a strong jet stream (which is consistent with the presence of the La Niña) were expected to contribute to a stronger season than we have seen so far. If we can’t understand why this season has been so quiet so far, it means we still have a lot to learn about hurricane climatology and behavior.

A large storm in the ocean

Description automatically generated with low confidence
Tropical Storm Lisa on September 23, 2016 with African dust

The second half of the 2022 season is likely to be a lot more active than the first half, although forecasters have dropped the predicted number of storms from the early forecast due to the past two quiet months. If you live in an area affected by Atlantic hurricanes, you should be prepared for a more active pattern—don’t let the last two months fool you! If you live in another part of the world that is affected by tropical storms, you should also understand their climatology and likely impacts on where you are as well.

A body of water with a sunset

Description automatically generated with low confidence
Caribbean rain shower at Man-of-War Bay, Tobago, September 1980. Source: NOAA.

Some resources for following hurricane weather

For those of you who are fascinated by tropical storms and hurricanes, even if you don’t live in an area that is prone to them, there are a few resources that you can use to track potential storms and follow them as they develop and move through areas that could be severely impacted by them. The first site I use is the National Hurricane Center, the source of official forecasts and outlooks for the season as well as specific storms as they form. Their website has a lot of information about past storms as well as educational resources on tropical systems. You can also find a lot of maps and climatological information at Mike’s Weather Page if you just need a quick look at maps and other images related to tropical weather in the Atlantic and Pacific Basins.

On social media, I follow Bryan Norcross and Brian McNoldy on Facebook and Twitter; they may be on other social media as well. Bryan Norcross is the television meteorologist who was working in Miami at the time of Hurricane Andrew; it has been fascinating this week to follow his timeline of Andrew from tiny disturbance to monster storm as it hit Miami and then Louisiana over the past week back in 1992, thirty years ago. Brian McNoldy is a senior hurricane researcher who works at the University of Miami and has done some interesting climatological work on past hurricanes as well as provides insight on the current season. There are also plenty of great local resources for local impacts if you live in a hurricane-prone area.

A picture containing nature

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Landfall of Hurricane Michael, October 10, 2018 from earth.nullschool.net

How to visualize the wind

If you are interested in looking at the wind patterns associated with storms, both tropical and extra-tropical, then there are three sources of fascinating maps that allow you to visualize the flow of air across the United States or the world:

United States current surface winds Hint.fm/wind. This site has a current map of the surface winds across the continental United States showing the wind speed and direction in motion. It is based on a near-real-time computer simulation to provide seamless coverage across the country.

Global earth interactive wind map https://earth.nullschool.net/. This interactive map allows you to look at current winds anywhere on the earth by dragging and zooming on the globe. You can use the menu on the lower left to pick higher levels in the atmosphere; this will allow you to look at jet streams aloft as well as surface winds.

Windy global current and forecast winds https://www.windy.com/. This site provides global current and forecast winds as well as other weather information that will allow you to view the weather and plan for future weather conditions at home or away.

These sites provide you with information about both wind speed and direction. That can be very useful for gardeners who are spraying or need wind information to track where the air hitting their gardens has come from. Wind drift of agricultural chemicals also causes damage to crops and outdoor workers. Exposure to chemicals such as weed killers can affect gardens adversely, and it can be important to know where those chemicals are coming from. If you don’t have access to local wind observations, these maps can provide you with useful information.

People and Plants

In this episode of P&P we’ll take a look at the life and career of the aptly named Nehemiah Grew, the “Father of Plant Anatomy”.

Nehemiah Grew
1641-1712

Nehemiah Grew was born on September 26, 1641 in Warwickshire, UK. He graduated from Pembroke College, Cambridge in 1661 and ten years later was awarded a MD degree from Leiden University in the Netherlands.
His interest in plant anatomy began to bud in 1664. In 1670 his essay, The Anatomy of Vegetables begun, was shared with the Royal Society and resulted in his election to the membership.
By 1672 he’d put down roots in London and soon had a large medical practise. Even though he was busy with his career as a physician he still found time over the next decade to write a couple of books, a few short publications on botany and several papers one of which has the intriguing title, “Comparative Anatomy of Stomachs and Guts” and was included in his “Catalog and Description of Rarities” publication, ca. 1681.

Photo courtesy of Royal Society (Great Britain) Museum.

In 1682 his tome, The Anatomy of Plants begun as a philosophical history of plants“, was published. It’s largely a collection of previous publications and is divided into four books, Anatomy of Vegetables begunAnatomy of RootsAnatomy of Trunks and Anatomy of Leaves, Flowers, Fruits and Seeds. It has eight-two illustrated plates and an appendix of seven papers which deal mainly with chemistry.
The book is noted for its descriptions of plant structure, a fairly unknown thing at that time. Grew described nearly all the key differences of stem and root morphology and showed that the flowers of the Asteraceae family are composed of multiple tiny tube flowers (florets). The most amazing of his discoveries was that plants reproduce sexually and that flowers are sexual organs. He distinguished and assigned “roles” to the calyx, corolla, pistils, and stamens.


Grew is remembered for being one of the first to establish the observational basis for botany and is noted for his detailed descriptions of plant anatomy. He utilized the microscope (invented in 1590) for his plant anatomy explorations and was a pioneer in this field. His book “Anatomy of Plants…” contains the first known microscopic description of pollen. He discovered that although all pollen is roughly globular, its size and shape varies between species; however pollen grains within a species are all alike. This discovery is central to the field of Palynology, “the study of dust”, which is the study of pollen and particulate samples both organic and inorganic.

Plate from Nehemiah Grew’s The Anatomy of Plants (1682)
Source 

Grew’s research technique was based on his adherence to observations and avoidance of explanations invoking occult, hidden or vital forces, or signatures. He also avoided the direct hand, intervention, or guidance by God or other spiritual beings.
He embraced a mechanical and natural philosophy which permitted him to think much like an engineer or how to make the most out of the materials at hand. This engineering concept was theologically acceptable during his time.
Why is this significant?
This ‘Mechanical way’ and Grew’s own theory of “Organ-ism”, that plants possess organs and structure, was outside the bounds of most of the thinking of his time. Before the 17th century it wasn’t certain that plants had much internal structure and that distinct parts or organs played distinct roles. It was often thought that the external shape of a plant was a clue or signature to its use, re: Doctrine of Signatures. But whether there was anything resembling organs in plants was contested. Grew’s detailed illustrations help dispel that belief and bring the study of plants into the scientific world.

Plate from Nehemiah Grew’s The Anatomy of Plants (1682)
Source

In honor of Nehemiah’s work and role as a founder of modern botany, Carl Linnaeus named the genus Grewia after Nehemiah Grew. Grewia is in the Malvaceae family and can be found in several areas including Africa, India, and Australia where it has naturalized and become invasive.
Its fruit comes in both sweet and tart varieties and is used for food and beverages. Other parts of the plant have been used medicinally.

Grewia occidentalis
Image by Giuseppe Mazza

Like to know more?
Part 1 | Christoffer Basse Eriksen: Nehemiah Grew and the Making of the “Anatomy of Plants” (1682) – Lecture

Part 2 | Christoffer Basse Eriksen: Nehemiah Grew and the Making of the “Anatomy of Plants” (1682) – Response & Panel Discussion

The 2022 Tropical Season: What are Tropical Systems?

In the Southeast, almost nothing gets more press than the Atlantic Tropical Season, including the outlooks, real-time events, and post-storm analyses. If you live in another part of the United States or the world, you may not be as directly affected as the Southeast is, but you might be surprised at how far and wide tropical moisture is spread, either directly by tropical storms and hurricanes or by the remnant moisture which can be carried with the winds for long distances away from their original sources. This week I will describe what tropical systems are and what they mean for gardeners. In my next post, I will review the current season, including any impacts that have occurred. Don’t let the early quiet conditions fool you—about 90% of Atlantic tropical activity occurs from mid-August through mid-October.

Hurricane lily (Lycoris radiata var. radiate). Source: Tonbu Mizo, Commons Wikimedia. For why they are called “hurricane lilies”, visit https://gardeningsolutions.ifas.ufl.edu/plants/ornamentals/hurricane-lily.html.

What is a tropical system?

I am using “tropical system” as a term that encompasses the life cycle of a tropical disturbance from birth to death. That may include formation by a tropical wave coming off Africa, developing in the Gulf of Mexico, or growing in the Eastern Pacific Ocean, then a tropical storm, a hurricane (maybe even a major one), and eventually a slow death as a tropical depression or extra-tropical low that has lost its tropical characteristics.

The map below shows historical tracks for all known storms across the globe. Note that in some regions they are called hurricanes and others, typhoons, but both are tropical cyclones, the generic name for rotating, organized systems of thunderstorms that originate over tropical waters and have closed, low-level circulations. The pattern of tracks shows some interesting information about tropical systems. For example, why are there almost no tracks in the eastern part of the South Pacific Ocean or in the southern Atlantic? Why do many of the tracks show a curve as the storm moves from east to west? Why are there more storms in the Northern Hemisphere (NH) than in the Southern (SH)? Why are there almost no tracks along the equator?

A picture containing nature

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Historical tropical storm tracks. Color coding indicates tropical depressions (green), tropical storms (yellow), hurricanes (red), and post-tropical storms (gray).

What ingredients are needed for tropical systems to develop?

Tropical systems form from areas of low pressure that develop rotation (counterclockwise in the NH and clockwise in the SH) as the storms’ pressure decreases. For the storm to strengthen, it needs favorable conditions to cause rising air in the center, which drops the pressure at the surface. One ingredient is ocean surface temperature of 80 F or higher (27 C)—that explains why almost no storms develop in the southeastern Pacific or southern Atlantic, since both are far too cold. Tropical storms and hurricanes are considered to be “warm core” systems with the air in the center of the storm staying warm all the way to the top of the circulation. The peak season of storms in the Atlantic is related to the cycle of ocean temperatures, with the highest likelihood of storms in the period from mid-August to mid-October. As ocean temperatures warm, this could mean a shift in hurricane season in the future.

For spin to develop, you need a force called the Coriolis force that affects the atmosphere due to the earth’s rotation around its axis. The Coriolis force is zero at the equator so any areas of low pressure that form in that area can’t develop the necessary spin to form storms. Another ingredient is light winds higher up in the atmosphere. This allows the vertical structure of the storm to develop a strong circulation that ultimately becomes a hurricane. This becomes important when we talk about the impacts of El Nino and La Nina on predictions of tropical seasons, since El Nino years have much stronger jet streams in tropical regions than La Nina or neutral conditions do.

The curvature of the tracks is due to the mid-level winds in the atmosphere that steer the storms as they go through their life cycles. The counterclockwise flow of air around ridges of high pressure systems push the storms along their edges. This often results in a C-shaped pattern as the storm travels around the western edge of the oceanic high pressure, although the position and strength of the high pressure will help determine the path each storm takes and when or if it recurves to the northeast.

Depiction of a hurricane life cycle, from a tropical disturbance (easterly wave off the West coast of Africa) to a fully formed hurricane. Image credit: NOAA/NHC.

Impacts of tropical systems

Some impacts of tropical systems are only found near the center of the circulation, but others can be found hundreds of miles away, so even if you are not in the main area that tropical storms affect, you are not without risk. These storms are not small whirls like tornadoes, but are much bigger and can take hours to cross a location near the center. If you are close to the storm’s center, especially if you are on the right side of the storm’s path, you are likely to experience strong winds, heavy rain, and, if you are near the coast, the chance of a storm surge coming inland from the ocean. Farther away, you can experience strong squalls that include small tornadoes, heavy rains, and gusty winds. These effects are made worse if you live in mountainous areas where lifted air can cause rapid flooding conditions. Some of the worst floods in U. S. history are from former hurricanes that traveled over mountains and dropped incredible amounts of rain, such as Agnes, which caused the death of 122 people mostly in Pennsylvania, almost exactly 50 years ago.

Even after a storm weakens to a depression or transforms into an extra-tropical storm, the blob of moisture within the remains of the storm can be transported by the atmospheric circulation a long ways. There have been records of typhoons in the Western Pacific Ocean whose watery remains crossed the ocean and brought heavy rain to the West Coast. Occasionally some will enter the central United States and drop flooding rain there, too, such as the remains of Tropical Storm Erin in 2007.

Hurricane Dennis batters palm trees and floods parts of Naval Air Station (NAS) Key West’s Truman Annex, U.S. Navy photo by Jim Brooks

What gardeners (and everyone else) should know

Preparing a garden for a hurricane is no different than preparing for other types of extreme weather. Survey your property before the season to make sure that no objects that could blow around in high winds damaged are present. If a storm is coming, make sure that your yard is free of garden gnomes, rakes, damaged tree limbs, or other loose objects that could become airborne. Make sure your roofs and gutters can shed heavy rain and have a place on your property to contain rainwater safely. Have supplies of batteries, non-perishable food, and water for people and pets. Put together a plan to recover later by making inventories of your property, including outdoor equipment that you store online. And make a family plan for how to evacuate if you live in an area of flooding and how to contact each other later if you get separated. Cell phones often do not work after strong wind events, so you can’t count on them to bring your family back together quickly after a storm.

What’s next?

I expect to see the Atlantic tropical season start to pick up by mid-August, when the African dust that is currently inhibiting storm formation clears and the ocean temperatures get even warmer. In fact, today’s 5-day outlook map shows an area of possible development in the eastern Atlantic (as of 8-6-2022). This is expected to be another active season, and even though we’ve only had three named storms so far, we will likely see many more storms before the end of November, when the official season ends. In my next blog, we will look at the season so far in more detail.

*Summertime, and the livin’ is easy…

If you listen closely you can hear the beasties in your garden just a-singin’ that tune. And who can blame them? Warm temperatures and lush green gardens? They enjoy them as much as we do. But sometimes they can be enjoying our landscape a little too much. So now what do you do?
Visit the garden chemicals section at your local big box store?
Reach for your favorite “natural” or DIY concoction?
Ask your neighbor?

Hmmm, maybe not.

What is the best way to deal with the problem?
Three letters answer that question.

IPM.

Scoutcat logo courtesy of C. Ware, copyright 2000


What is IPM? Integrated Pest Management (IPM) is the management approach you should use to solve pest problems. It can manage all sorts of pests with minimal risks to people, pets, and the environment. IPM’s emphasis is on the management of problems rather than eradication. It focuses on long-term prevention of pests or their damage by managing the ecosystem.
IPM is a five step process: 1) correct pest ID, 2) monitoring and assessing pest numbers and damage, 3) pest ID guidelines for when management action is needed, 4) preventing pest problems, and 5) determining correct control measures. Let’s take a look at each one.

#1. Pest ID

Correct ID of the problem-causing critter is the most important aspect of IPM. If you don’t know what you’re dealing with, how can you devise an effective control strategy, if indeed one is needed?
So what is a pest? Pests are organisms which damage or interfere with desirable plants or damage structures. Pests also include organisms that can impact human or animal health. Pests may transmit disease or may be just a nuisance. A pest can be a plant (weed), vertebrate (bird, rodent, or other mammal), invertebrate (insect, tick, mite, or snail), nematode, or a pathogen (bacteria, virus, or fungus).
A correct ID of the pest must be made before deciding if control is needed. If you aren’t sure you’ve ID’ed it correctly or want a second opinion, take a sample to your local Cooperative Extension Service Office.
Note: Be careful about asking for pest ID at a garden center. Employees may not be knowledgable, or your request might be seen as a sales opportunity. And think twice before taking the advice of someone who might try to sell you something.

It never hurts to ask for more input on an ID.


#2. Monitoring and Assessing Pest Numbers and Damage.

You’ve probably heard the saying, “The best fertilizer is the gardener’s shadow.” I’ll make the claim that “The best pest control method is the gardener’s shadow”.
For effective monitoring, you need to be out in your garden on a regular basis. Looking, listening, even handling plants, checking under leaves, etc., so you come to know it as well as you know the layout of your living room. You should have a good knowledge of your landscape’s microclimates, soil conditions, the path of sunlight through the year, how seasonal changes affect your garden and a general grasp of the climate. Once you know what’s “normal” for your landscape it’ll be easier to spot any abnormalities.


For example:
Your favorite rose always has a few aphids but the population seems to have exploded in the last few days. And why do some of them have wings?
Is that slug damage on that hosta?
You don’t recall seeing those rusty patches on that hollyhock before.
What are the odd black spots on this pomegranate?
Hmm….
Always ask yourself how extensive the damage is. Does it threaten the health or life of the plant, or is it largely cosmetic? Do you need more expert advice?
Continual monitoring and assessing of what’s going on in your landscape can help you decide if the damage is important or extensive enough to require pest management.

#3. Pest ID Guidelines to Determine if Management Action is Needed

Which one is the pest? They both seem surprised.

Using the biological information of the correctly ID’ed pest will help you decide if you need to deal with the situation. Here are some things to consider when deciding if management is needed.
Is the pest short-lived and is only in the garden for a few weeks or even days?
Does it only make a seasonal appearance?
Is the damage of long duration/the entire growing season, only for a short time and the plant recovers, or is the damage mostly cosmetic?
Is it a pathogen?
Does it carry a pathogen?
Can it cause irreparable harm?
Is it an invasive species that can or should be controlled?
Does it threaten a needed food garden?
Is the damage really that bad?

Knowing the life cycle and feeding habits of your ID’ed pest will help you determine if control is necessary. Use their biology against them. Do your homework.

So you have a plant issue and you’ve correctly ID’ed the pest and the problem. It needs to be dealt with.
What’s your next step?

“And you may ask yourself, “How do I work this…”?
Once in a Lifetime
by the Talking Heads


#4. Preventing Pest Problems

“An ounce of prevention is worth a pound of cure.” applies to landscapes as well our personal health.
Ask yourself if the garden problems you’re facing, most of which will be cultural, can be handled with preventative measures.
Are you over or under watering? This stresses plants which can attract pests.
Is the plant that is under attack in a less than optimal location? Can you move it or change its environment to help it become healthier? Or should you just remove it and let the Japanese beetles eat somewhere else?
Are you practicing good garden sanitation, are you cleaning up those camellia leaves and blossoms after they fall, are you turning that compost pile and ensuring it heats properly in order to kill pathogens or pests?
If your growing zone allows it, perhaps you could plant your summer squash or tomatoes later and avoid that first rush of squash bugs or hornworms? (Keep in mind that hornworms are larval sphinx moths which are an important bat food source.)
Have you tried using row cover to exclude problem insects or other pests?
Be sure you’re not causing the problem. A little garden evaluation can do a world of good.
The decision you make here will determine the road you take in dealing with your pest issue. You’ve identified the pest, done some sleuthing and have an idea of the scope of the problem in your landscape. Now you have to decide what is the acceptable level of this pest to have in your yard.
And as always, “Right Plant, Right Place”.

#5 Determining Correct Control Measures

Start at the base of the pyramid when choosing control measures

After analyzing the situation you’ve determined you need to engage in some form of pest control. But what should you use? Always strive to use the most benign yet specific form of control you can. Use the method which best targets the problem.
A combination of control methods usually give the best results. These include biological, cultural, mechanical/physical, and chemical/bio-rational measures. Start at the base of the pyramid (see above image) and work your way upward. Always allow sufficient time for methods to yield results. Pest problems rarely happen overnight. Early intervention is the key to control. See #2 above.


If you are forced to use pesticides always use them as a last resort, not as a first option.
Avoid using systemics on plants which are used by pollinators or other beneficial insects.
Avoid using broad spectrum pesticides and keep in mind that many pesticides which are approved for “organic” use are more toxic and less selective than “synthetics”.
An exception to the “avoid broad spectrum pesticides”: there can be times when a broad spectrum herbicide, such as glyphosate, is needed to kill both monocots and dicots. Use with care and follow label directions.

Always target the specific pest or problem.

To review:
Please follow the IPM Five Step Process:
1. Always ID the pest correctly.
2. Get to know your own landscape. Monitor and assess pest numbers and damage to determine if intervention is truly needed. It often isn’t.
3. Use the pest’s life cycle and feeding habits to decide if or when management action is needed. Use their biology against them.
4. Prevent pest problems in the first place. Be sure you’re not part of the issue. “Right Plant, Right Place.”
5. If necessary, determine the correct control measures and always choose the most benign method which will do the job. Keep in mind products labeled “natural” may not be the best or safest option. Avoid DIY concoctions. They’re usually ineffective, harmful and an illegal use of ingredients.

Garden smarter, not harder.

Want to learn more about IPM?
http://www.npic.orst.edu/pest/ipm.html
https://ipminstitute.org/what-is-integrated-pest-management/
https://www.usda.gov/oce/pest/integrated-pest-management
https://www.epa.gov/safepestcontrol/integrated-pest-management-ipm-principles
Regional IPM centers

And last but not least:
* Link to my favorite cover of this great George Gershwin tune

Water Woes

If you live in a place where water falls from the sky during summer this blog is perhaps not so helpful. However, gardeners in much of the western United States will suffer this summer from hot days (sometimes record breaking) and will need to irrigate their gardens and trees in order for them to survive impending drought conditions. The ongoing drought has drained reservoirs and flows of rivers are down or, in some cases, dry entirely. Due to water scarcity, purveyors are restricting water use outside of homes and in some cases curtailing all landscape irrigation. Using water wisely in the landscape has never been more relevant than now. In this blog post we’ll continue to explore saving our gardens from drought and touch on water use, water demand and plant stress.

Good news — Bad news

The good news is that the longest day of the year was last month. That means that the days are ever so gradually getting shorter. As days shorten, plants use less water. Water use is tied directly to photosynthesis and when the lights are out there is no photosynthesis. Shorter days mean less demand for water. The bad news is that we may have record breaking hot days ahead. Plants become susceptible to wilt, sunburn and dieback during very hot weather. The best way to prevent this is to ensure that roots are moist during very hot weather.

The combination of drought and heat caused sunburn to these privet leaves

Mediterranean Climate

It turns out that in Ventura, CA the longest day of the year is one of the historically driest months (least rainfall) and the shortest day occurs in a month with more rain than average. This is a classical Mediterranean climate, the rain falls when we least need it for thirsty plants. Plants may not use all the water that falls in winter but soil is leached of salts and deeper soil layers are filled with water. Large woody plants can utilize this deeper soil water in drier months.

In a Mediterranean climate little rain occurs in the summer months

Stress

What is not obvious is that stress, especially water stress, is not highest on the longest day but occurs and builds later in the summer and fall months. This is because water is slowly depleted from soils over time. Water use is compensated by irrigations during dry months so stress may not build depending on the effective use of irrigation to keep plants hydrated. Plants and gardens that are less reliant on irrigation build stress over time CUMULATIVELY until they are irrigated or rain falls again. So after the spring rains stop, the “stress clock” starts ticking and keeps building until rain or irrigation happens again in the fall or winter. It is no wonder that symptoms of stress such as wilt, sun burnt leaves, leaf fall and plant death occur in late summer when cumulative stress levels overcome plant physiological limits. Late summer often is the time when the hottest days occur and heat stress in addition to drought stress adds to the struggle for garden plants.

Adding stress bars (red) shows how stress builds over time if there is no rainfall or irrigation

Save your plants in the fall from deadly stress

In the late summer or fall months plants are most likely to die of drought induced stress. This can be forestalled by irrigation applied in August which will reset the stress clock to lower levels. Stress won’t return to low wintertime levels because irrigation water is often of less quality than rain water. The salts in the irrigation water raise the osmotic potential of soil water creating another kind of stress. When it rains, these salts are washed from soil and plants are at their lowest stress levels.

Monsoons (see recent blog by Pam Knox) provide arid climates with stress relief when plants growing in hot deserts most need it. Many plants come out of dormancy or germinate only after the onset of summer rains. While monsoonal moisture can be unpredictable usually some rain falls in the desert southwest. In years when the monsoons don’t come or provide only low amounts of water, some trees or other woody plants even cacti, may die from stress.

Monsoons in Portal, AZ, July 2022.

Monitor your plants for stress as long dry periods or hot weather get longer and hotter. Apply water strategically to take off stress. Irrigate deeply by soaking the root ball(s) of the plant(s) you want to save. Established plants are pretty tough and can survive adverse periods, newly planted specimens not so much. They must be irrigated frequently just like they were in the nursery until their roots are will grown into site soils. For those of us living in a Mediterranean or monsoon climate we should wait until the onset of a wet period is near before installing new plants.

People and Plants

This Independence Day weekend blog post is about John Bartram, the American gardener and botanist who revolutionized gardening.

John Bartram was born a third generation Quaker on a farm in Darby, Pennsylvania on March 23, 1699. While he had no formal education beyond the local school, he was interested in medicine and medicinal plants. Stymied by the lack of local medical schools, his interests gradually turned to botany and he became one of the first practicing Linnaean botanists in North America.

In 1728, Bartram purchased 102 acres of farmland and 10.5 acres of marshland along the Tidal Schuylkill River from Swedish settlers. After establishing his farm and building his house, he laid out his first garden across six or seven acres on a terraced slope leading from the house to the river. His farm and collections expanded over time and have since been recognized as the first botanical garden in the USA.


Bartram made many plant collecting trips, the first documented one to the “Jerseys and Schuykill mountains” in 1735. His many travels by boat, horseback, and on foot, took him to New England, south to Florida, and west to Lake Ontario. While traveling he collected seeds and plant specimens, assessing how best to cultivate them back home in Philadelphia and how to share his discoveries. Other Colonial-era plant nerds supported his efforts and shared unique plants from their own collections.

Through his seed and plant sharing network Bartram became associated with Peter Collinson, an English merchant, fellow Quaker, and Royal Society member. Collinson, also a plant lover, shared seeds and plants with fellow gardeners, many well placed in British society.

Encouraged by Collinson, who eventually became his chief agent in London, Bartram established an international trade in North American seeds and plants packed carefully in wooden “Bartram’s Boxes” which were shipped in the fall. For five guineas, clients received a container of generally 100 or more varieties of seeds, as well as occasional dried plant specimens and other natural curiosities like bird nests and rocks. Despite the hazards of a sea voyage, many arrived safely to their destinations, where they established a new palette of American colors and shapes within European gardens and landscape.

Bartram’s nursery business continued to grow and thrive with sons William and John Jr. joining the business. Bartram and William continued their plant collecting journeys around North America. In October of 1765, after becoming lost on one of their trips near the Altamaha River in southeast Georgia, they came across the “rare and elegant flowering shrub” Franklinia alatamaha. Of course they collected specimens, which is fortunate for us as the plant appears to be extinct in its original native range. It survives today in cultivation because of the Bartrams’ efforts (you can read this interesting article for more on the topic).

Franklinia bloom
Photo by Tom Potterfield licensed by CC BY-NC-SA 2.0

After lobbying by Collinson and Benjamin Franklin in 1765, King George III granted Bartram a pension of £50 per year as the King’s Botanist for North America, a post he held until his death. In this position, Bartram shipped his seeds and plants to the royal collection at Kew Gardens. Bartram also contributed seeds to the Oxford and Edinburgh botanic gardens. In 1769 he was elected a foreign member of the Royal Swedish Academy of Sciences in Stockholm.

John Bartram’s house as it appears today

Bartram, the “Father of American Botany,” died in 1777. His sons, William and John Jr,. continued the family business of North American plants after the American Revolution. A total of three generations of the Bartram family continued to operate and expand the botanic garden. It was considered the major botanic garden in Philadelphia until the last Bartram heirs sold out in 1850. America’s oldest surviving botanic garden was dedicated as a 50 acre National Historic Landmark in 1963. Be sure to visit when you’re in the area.

Interested in learning more about John Bartram and other revolutionary gardeners of his time? There’s an excellent book by Andrea Wulf, “The Brother Gardeners“. I highly recommend it.

ISBN-10 ‏ : ‎ 0307454754
ISBN-13 ‏ : ‎ 978-0307454751

Happy Independence Day and here’s to garden revolutions everywhere!

Franklinia alatamaha by William Bartram (1782)