September 2022 – The Garden Professors™

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 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 2/3^rd 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 can be used well, but more often simply add misery to trees and aesthetics*

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.

*Each one of these bags delivers water **outside** the planting hole, which encourages root growth outwards.*

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?”

*Various tree irrigators of dubious value. Note presence of weeds and/or lack of water in devices.*

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.

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.

Bee Lawns: What’s all the buzz about?

A bee lawn is a way to benefit pollinators in our landscapes by providing additional floral resources, and often utilizes a mix of low-growing flowering plants in addition to turf species. Although flower gardens also provide flowering plants for pollinators, bee lawns can be multi-functional in their usability for recreational purposes with the added benefit of providing food for bees.

Habitat loss is one of the major factors implicated in the global declines of native bee species. Providing resources utilized by these critical pollinators can assist in mitigating this. Research through University of Minnesota has found 50 species of bees utilizing the flowers in bee lawns.

The purpose of bee lawns includes providing nutritious sources of nectar and pollen for pollinators, especially in urban environments, where these resources can often be scarce and difficult to find. Additional factors include recreational usability, and reducing inputs, e.g., irrigation, nutrients, weed control, and time spent mowing. Flowering plants suited for bee lawns have a variety of common characteristics including: low-growing and flowering heights, perennial life cycles, the ability to persist with turf species, and tolerance of mowing and foot traffic.

An important consideration is that bee lawns don’t necessarily mean weedy lawns or no-maintenance lawns, but instead require different types of management and serve different functions than traditional turfgrass lawns.

Not all bee lawns are created equal, and some work better than others.

Here are some turfgrass species that can work well for bee lawns:

Cool-season turf

A mix of fine fescues (which includes species such as: creeping red fescue, chewings fescue, hard fescue, and sheep fescue) are some of the best options for bee lawns due to reduced needs for inputs including irrigation, fertilizer, and weed controls, in addition to their compatibility with flowering plants. That being said, fine fescues do not tolerate heavy foot traffic, and may not be a suitable option for turf varieties in areas with heavy recreational use.

Kentucky bluegrass (KBG) is another option for bee lawns, though it requires higher maintenance (including more frequent irrigation and fertilizer inputs). KBG is considered an invasive species in some areas so do your homework.

Warm-season turf

Although there is limited research currently available for warm season turfgrasses and their compatibility with flowering plants specifically for bee lawns, certain species require lower inputs and could be a good option.

Centipede grass is a suitable option for a low-maintenance warm season turf species, and has been utilized in studies evaluating early-spring flowering bulbs as part of a lawn ecosystem for pollinators (see resources for more information).

Bermudagrass can also be used with flowering plants, though it has higher input needs than centipede grass. For more detailed information on warm season turfgrass species suitable to your geographic area and their respective input needs, I would encourage you to reach out to your local and regional extension offices.

Here are examples of flowering plants that can work well with turfgrass species:

Dutch white clover (Trifolium repens)

Dutch white clover (often referred to as white clover or clover) is a common occurrence in many lawns. Although some consider this to be a weed, white clover can provide several benefits including its adaptability to many soil types, the ability to withstand some shade and foot traffic, and the added benefit of being able to fix its own nitrogen. Like its name suggests, white clover produces white (and sometimes pink) flowers, and grows to a height of 4-6 inches. In addition to its hardiness, white clover is also an excellent source of forage for bees due to its long bloom time, and the great quality of nectar (high sugar content) and pollen (high protein content).

Dutch white clover flowers in a lawn (Photo: Whitney Cranshaw, Colorado State University, Bugwood.org)

Creeping thyme (Thymus praecox)

Creeping thyme is related to some of our favorite culinary herbs, and produces fragrant purple/pink flowers. It has a low growth habit (<6 inches) and can tolerate some foot traffic. It performs best in well-drained sandy or loamy soils, and is also considered to be drought tolerant and deer-resistant.

Self-heal (Prunella vulgaris ssp. lanceolata)

Self-heal is native to North America, Europe and Asia, and research from University of Minnesota has shown that 95% of the pollinators that visited the flowers were native bee species. It produces purple flowers and does well in a variety of soil types (with the exception of sandy soils) and in sun or partial shade.

Self-heal flowering with turfgrass (Photo: John D. Byrd, Mississippi State University, Bugwood.org)

Common violet (Viola sororia)

Violets are another flower that some consider to be a weed in home lawns. These spring blooming yellow, purple, and white flowers can be a good source of nectar for pollinators such as butterflies and bees. Violets grow to heights of 4-8 inches, and do well in a variety of soil types in addition to sun and shade.

Purple flowers growing in grass — Violets growing in a lawn (Photo: Sarah Eilers, Montana State University)

Other flowers

Additional low-growing flowers could also be great additions to bee lawns, including early spring flowering bulbs that can persist with turfgrass for multiple years, such as crocus and grape hyacinth (Muscari spp.), which have been observed to attract pollinating insects (especially honey bees).

For more information on the regional suitability of flowering plants to incorporate with turfgrass for bee lawns, contact your local extension offices for more information.

University of Minnesota’s Bee Lab has a lot of excellent information on bee lawns, their establishment, and the diversity of bees that visit them:
https://extension.umn.edu/landscape-design/planting-and-maintaining-bee-lawn#turfgrasses-for-bee-lawns-2939360

https://turf.umn.edu/news/if-you-build-it-who-will-come-evaluating-diversity-bees-flowering-lawns

Additional Resources:

https://www.canr.msu.edu/news/consider-a-flowering-bee-lawn-to-help-pollinators

https://extension.psu.edu/the-buzz-about-bee-lawns

Wisdom, M. M., Richardson, M. D., Karcher, D. E., Steinkraus, D. C., & McDonald, G. V. (2019). Flowering persistence and pollinator attraction of early-spring bulbs in warm-season lawns. HortScience, 54(10), 1853-1859.
https://journals.ashs.org/hortsci/view/journals/hortsci/54/10/article-p1853.xml

Larson, J. L., Kesheimer, A. J., & Potter, D. A. (2014). Pollinator assemblages on dandelions and white clover in urban and suburban lawns. Journal of Insect Conservation, 18(5), 863-873.
https://link.springer.com/article/10.1007/s10841-014-9694-9