Month: December 2021

This week is the end of 2021 and the start of the new year. What a year 2021 has been! Without even talking about politics, COVID-19, sports, or the economy, it was certainly one to remember from the standpoint of weather and climate. No matter where you live, you probably saw some extreme weather during the past 12 months.

Exploding flower bed fireworks, Eric Kilby via Commons Wikimedia.

Extreme weather in 2021

In the United States, the map below shows just the 2021 billion-dollar disasters through October 8. That does not include the tornadoes that ravaged the Midwest, including Mayfield KY, in early December or the fires that burned through the suburbs between Boulder and Denver CO, earlier this week, since those losses have not yet been tabulated. This also does not include the terrible disasters that happened in other parts of the world, such as the devastating spring frost in France’s wine country or the awful flooding in parts of Germany and Belgium last summer. While there is no doubt that a warming climate is partially to blame for many of these disasters, we are also putting ourselves in harm’s way by building in areas that are prone to flooding, wildfires, and other natural hazards that can lead to human disasters. Even if the climate were not changing, we are making matters worse by putting ourselves at higher risk in the way we build and develop land.

Looking back over last year’s climate

Climatologists are generally very busy this time of year, since everyone (especially the media) wants to know how the year that just ended compared to previous years. While it usually takes a few days for the preliminary data to be complete, and a few months before the final quality-controlled data are available, we can take a quick look at the past year using online tools like the High Plains Regional Climate Center’s ACIS Maps that compile climate information into simple displays. The map below shows the percentage of normal rainfall for 2021 across the contiguous United States. As usual, there are areas with very wet conditions and areas that received less than a quarter of their expected precipitation. Sometimes those areas are not very far apart—just compare southern California with Arizona right across the border. Does the map agree with what you experienced?

If we look at the temperature map below, it shows that very few areas in the United States were colder than normal temperature. What makes this particularly concerning is that our normals were just updated this year, as I discussed in an earlier blog post. Because the temperature trend across the United States is upward, not flat, we can expect to see more years above than below normal in the future. This is leading to concerns about increased water and heat stress on gardens and gardeners who are working outside as well as damage to natural ecosystems not adapted to the warmer temperatures.

Reviewing your garden in 2021

New Year’s is a great time to evaluate the past year and plan for the next twelve months in your garden, too. If you have the chance, take a walk through your garden and see how it looks (of course, that assumes it is not covered by snow). How did your plants, shrubs, and trees do this year? Are new plantings well established, or do they need to be moved or replaced? Are your new trees correctly planted and growing well? Are you maintaining soil health and moisture with appropriate surface cover? If not, there is plenty of advice on how to correct problems in this blog—just do a search to find information that is based on current science, not hype. It’s also a great time to think about what you will be doing with your garden in the coming year. Perhaps the warmer temperatures will allow you to try new plants that you have not been able to grow before. I know many of you are already looking at the new seed and garden catalogs for next year, so dream away!

Don’t forget to prepare for bad weather, too

In addition to your planning for next year’s garden, don’t forget to prepare for extreme weather, too. Have a plan for where to go when severe weather threatens, and how to contact each other if you are away from home when it strikes. Keep an eye on weather forecasts so you know when conditions are likely to threaten. Have multiple ways to get severe weather warnings, including a NOAA weather radio and a cell phone that is charged and ON with the volume turned up and an appropriate warning app or two loaded. Don’t count on an outdoor siren to wake you up—they are not designed to warn people indoors. Get helmets to protect your heads from falling or flying debris if you can. Make an inventory of your household goods and store it somewhere safe (a good idea for any disaster, not just a weather event).

See you in 2022!

I’ve enjoyed sharing some of my weather and climate knowledge with you over the past few months and look forward to continuing this in 2022. I’ve also learned a tremendous amount from my co-authors and know that you have, too. Enjoy the rest of your winter holidays! I hope that your 2022 is beautiful, safe, and productive for all of you and your gardens too.

Auntie Mame was on to something when she told her orphaned nephew Patrick to “Haul out the Holly, Put up the Tree Before My Spirit Falls Again” (I just sang this in a concert with my community chorus.  I’ve been hauling out the holly since August, so I’m done.) 

Plants play a big part in our holiday traditions this time of year.  When it comes to decorating for the holidays, needless to say I prefer a simpler, natural approach. The best inspiration — and materials — come from nature and sometimes from your very own landscape. It is no secret that the celebration of Christmas was timed by early church leaders to coincide with other ancient winter festivals that predate Christianity.  It made it easy to get everyone to join in the celebrations. 

Saturnalia was a Roman festival that celebrated Saturn, the deity of agriculture, and the harvest. Yule was a 12-day midwinter festival celebrated by Germanic pagans into which Pope Julius I inserted Christmas in AD 336 (there was no celebration of Christmas until then), giving rise to the 12-day Christmastide festival (or Yuletide, depending on where you are). The celebration of the winter solstice is also of pagan origin, a celebration of the darkest, or shortest, day of the year (in the Northern Hemisphere) and the rebirth of the sun.

Many of these festivals included the bringing of evergreens and natural elements indoors to celebrate the connection between humans and nature. They were a sign that life would return after the cold, harsh winter. And also a way to bring a little cheer indoors to brighten up the home during the cold, dreary winter. 

If you look at many of the more traditional elements of Christmas, you’ll notice their connection with nature, and specifically plants — evergreens, holly, amaryllis, poinsettias and more. Of course, the star of the show is the Christmas tree. Christmas trees as we know them didn’t debut until the 16th century in Germany.

A prickly holiday tradition

I’ve written about several holiday plant traditions over the years, each a different way to look at a plant that or plants that bring tradition and cheer into the home.  Perhaps the most popular of these articles is about one of the most recent additions to the holiday plant family – cacti.  The interest in this holiday plant is surging thanks to the interest in houseplants at the moment.  This is making an issue I pointed out several years ago in the article A Cactus by Any Other Name: A Case of Mistaken Holiday Cactus Identity about the mis-naming of cacti even more important.  There’s a Christmas cactus, but there’s also a Thanksgiving cactus (and an Easter one, too). 

Thanks to years of marketing and selling Thanksgiving cacti as Christmas cacti (since they bloom early enough for the Christmas shopping season and actual Christmas cactus bloom closer to Christmas), many people confuse the two.  This isn’t a big issue for the casual holiday plant shopper, but for those that “collect” the plants it can be an issue trying to sort out which is which.  For example, someone recently posted in a local plant group that they were looking for a Christmas cactus.  Half the responses were telling them where they could buy a Thanksgiving (more commonly called Zygo cactus after the zygomorphous shape of the flower) cactus and the other half were asking if they meant that they wanted a true Christmas cactus or a Thanksgiving cactus. 

As romantic as poop on a stick

As holiday plant traditions go, the hanging of mistletoe has to be both the most interesting and weirdest.  As tradition goes, if two people meet beneath the mistletoe they’re supposed to kiss.  How did kissing become associated with a toxic plant that parasitizes trees and whose name translated from the Anglo-Saxon means “poop on a stick” from the fact that the seeds are spread by bird droppings? 

As I shared in The Myth, the Legend, the Parasite: Romance, Lore, and Science beneath the Mistletoe, Norse legend has it that the goddess Frigga (Frig, or Fricka) made everything on earth promise to not hurt her beloved son Baldr, but she forgot to ask mistletoe since it was so small and innocent looking.  Baldur’s brother, the trickster Loki (you know, the one in all the movies these days) made a spear of mistletoe and that ended up killing Baldr. The white berries of mistletoe represent Frigga’s tears, and she decreed that the plant should represent love and that no harm should befall anyone standing below it.  And there you have it.

The flower that’s really just a bunch of overachieving leaves

Most recently, I shared a bit of history and lore around poinsettias, that common but prissy holiday plant that most people can’t keep alive more than a few weeks.  I mean, the original Aztec name for the plant, cuetlaxochitl (ket-la-sho-she), can be translated as meaning “flower that withers” or “mortal flower that perishes like all that is pure”, so the reputation fits. The actual flowers of the plant are the ugly little greenish-yellow bits in the center, which are highlighted by leaves, called bracts, that change colors to bright red (and more colors now) as the flowers develop.

The flower and the bright red represented a gift from the gods for the sacrifices that the Aztecs would make to them. You can read a bit about the history, and how to save them and get them to rebloom from year to year (if you dare) in my festive little ditty Poinsettias: from ditch weed to holiday super star (history, lore, and how to get those d@!% things to rebloom next year).  Of course, there’s been recent discussion on how the story of the poinsettia is similar to the pagan traditions associated with Christmas – a plant tradition of the Aztecs was changed as a way to fit with the Christmas story and work as a conversion tool. It is good to know a bit about the original tradition of the plant to understand its importance throughout history. 

Haul out the holly….and the magnolia….and the rhododendron…..

Holiday plant traditions don’t stop at those finicky plants we grow in greenhouses- the original traditions of Solstice and Yule consisted of bringing in all different types of plants for the season. Sometimes you have to look no farther than your yard to find natural elements fit for a holiday celebration. If you have evergreen trees or shrubs in your landscape, they can easily be incorporated into holiday arrangements indoors or out.

While you can readily purchase live Christmas greenery at many retailers and markets (except for this year, with all the supply issues going on), what you can harvest from your own yard or nearby woods (where permissible) will be much fresher and last much longer. Remember that harvesting branches from your own trees and shrubs is actually pruning them, so you can kill two birds with one stone.

Both white and Virginia pine make excellent decorating choices as they are long-lived and retain their needles well. Junipers, cedars and firs all have interesting foliage and wonderful evergreen scents. Junipers can sometimes be found with berries and cedars sometimes have tiny cones. Spruce is a great choice for wreaths, as it is bristly and holds its shape.

Decorating doesn’t have to be left to the needled evergreens, though. Holly is a classic choice, but mountain laurel, rhododendron, boxwood and magnolia and many others can provide beauty and elegance in holiday displays.

You don’t even need to stick with green things in your decorating, either. Attractive bare branches, plumes from ornamental grasses and other “brown” things can add contrast. Other natural items, such as fruits, nuts and pinecones can also be incorporated for color and interest.  Just take a look around your yard or neighborhood to find those natural elements to bring indoors.

To keep your greenery fresh, there are some basic tips that you can follow:

• Use sharp pruners to make cuts, and keep the ends of branches in water until ready for use.
• Soak evergreens in water overnight to absorb moisture and extend shelf life.
• Keep arrangements in a cool location until use.
• Keep evergreens out of sunlight to reduce moisture loss.
• Use an anti-transpirant spray to keep in moisture.
• Don’t decorate too early — live plants have a limited lifespan.
• If purchasing plant materials, select healthy, green plants and flexible needles/leaves.

Very large and old trees don’t often attain size and splendor free of defect and disease. A mature tree may have accumulated some damage, injury or disease along its path to grandeur. It can contain hazardous branch attachments that have not failed yet, large sections of dead wood or it may bear the burden of an assemblage of cables and other devices installed over the years to sustain it. Very old mature trees have endured perhaps multiple human lifetimes of exposure to storms, droughts, pests and, perhaps worst, early pruning practices. Trees gain age and majesty when they don’t fall down or fail multiple large branches. To do this trees defend their wood biochemically from invading fungi. Trees also cover over decayed wood with new wood that is fairly impervious to the old infection. High vigor trees with adequate resources (water, soil, sunlight) should be able to contain decay that would shorten their lives otherwise.

Dr. Alex Shigo (2003) devised a chart showing the amount of pruning over a tree’s life time. Young trees have all living cells and most of the wood is sapwood, therefore the trimmings in young trees are of living tissues. As trees grow older and shade themselves heartwood develops in the canopy. It’s not living, doesn’t conduct water and minerals but does provide support to branches and strength to the canopy. Heartwood is also more resistant to decay than sapwood. The pruning of a mature tree removes a combination of living and dead cells. An over mature or ancient tree has much more dead cell tissue and only deadwood should be removed with an attempt made to preserve all stems with leaves.

Large trees have large branches and the temptation is to remove large branches to achieve pruning objectives. This would get more done and we would then have to prune less, right? But this is a flawed strategy and the results are the opposite of what the tree owners are trying to achieve. As trees get large, pruning cuts should be smaller and occur frequently. Guidance can be given to branch growth by many small cuts rather than large ones. This approach directs growth without causing rampant regrowth of dormant or latent buds. Latent buds have a purpose, they rescue trees from death should there be a catastrophe. They are preformed along large branches and will sprout when exposed to sunlight or when the terminal buds are removed. Large topping or heading cuts typically activate latent buds and the tree subsequently grows back too many branches in one place. These require selection and careful removal over time and can involve quite a bit of repair pruning to fix the tangle cause by massive heading cuts. Aging trees develop an extensive heartwood that is easily exposed to decay from large pruning wounds so large cuts should be avoided.

Larger trees develop more sapwood which needs energy for respiration relative to the amount of leaves in the canopy. The first duty of the leaves is to provide energy to keep all the cells in the young phloem and sapwood metabolically active. A typical tree only utilizes a few growth rings of sapwood for water transport and energy storage. As these rings age they narrow and there is less tissue from which to store and retrieve energy. Despite the subtle balance between canopy and energy utilization trees continue to grow throughout their lives at more or less the same rate. As trees age the amount of non-functional wood increases, this may be heartwood or deadwood in the canopy. At the end of their lives trees have nearly no living sapwood and the energy of the tree is mostly depleted. Over pruning causes further energy depletion. Removing leaves and buds that give rise to leaves from old trees reduces the amount of energy stored. This forces the tree to utilize sapwood reserves to recover from the pruning losses of the photosynthetic part of the tree. Severe pruning in old trees ultimately depletes them of stored sugars and leaves them without energy to make defensive compounds. This can exacerbate conditions by allowing disease or decay organisms to enter the sapwood.

What if your large tree was never structurally pruned and has branch faults or you have concerns for failure? You should always consult a certified arborist with training in Tree Risk Assessment. The health of the tree is important but the safety of those living around it is more important. Sometimes targeted pruning can be used to shift the balance of growth in a tree and strengthen branch attachments. This can take years of careful pruning with small or modest cuts. When large branches must be removed they should be left as long as feasible and the cut should be circular not an oval shape to decrease exposed surface area. Large pruning wounds should be limited to the fewest number required to achieve the pruning goal. Pruning paints and wound dressings are not recommended.

Large trees accumulate deadwood during natural senescence of inner branches or due to injury, disease or insect attack. Common practice has suggested removing deadwood from old trees but as arborists become more sensitive to urban ecology issues we realize that deadwood is prime habitat for cavity nesting birds and other life. Deadwood serves a purpose and, if it does not pose a threat to those living under or around the tree, it should be retained especially if evidence of utilization is present.

Caring for large trees is tedious because there is a lot at stake. Old trees are valuable and provide many benefits to their owners. Always seek expert opinions and be willing to pay for them, preferably from the arborist who does not do the pruning. Then act on those opinions with care and consideration and always closely supervise any pruning being done to your trees.
Use the following pointers from Gillman for mature tree pruning strategies:
-Evaluate your tree for health, strong branch structure and evidence of decay
-Remove dead branches as needed but retain some for wildlife if needed
-Perform structural pruning when feasible
-Shorten or remove branches with cracks swellings or deformities
-Remove parasites such as mistletoe or canker infested branches
-Retain as much live tissue as possible while achieving pruning objectives
-Keep cuts small (2inches) or moderate (4″) if the tree is a good decay compartmentalizer

References:
Gillman, E.F. 2012. An Illustrated Guide to Pruning 3rd ed.
Delman Cengage Learning, Clifton Park, NY.
Manion, P.D. 1991. Tree Disease Concepts. 2nd ed. Prentice-Hall, Englewoood Cliffs, N.J.
Shigo, A.L. 2003. Modern Arboriculture A systems approach to the care of trees and their associates. Shigo and Trees Associates Durham, NH. 3rd ed.

Welcome to the first People and Plants GP blog post. These posts, which will be on a random basis, will take a behind the scenes look at the namesake people behind many plant names. This first one will be about Andrew Jackson Downing.

Andrew Jackson Downing was born October 30/31, 1815 in Newburgh, New York to Samuel Downing and Eunice (née Bridge) Downing. His father was originally a wheelwright but later became a nurseryman. After he finished his schooling Andrew worked in his father’s nursery and was soon bitten by “the plant bug”. I’m sure many of us can identify with that “affliction”.
Over time he became more interested in landscape gardening, architecture and the relationship between them. He began writing articles about botany and landscaping but soon realized he needed to know more about both topics and so began a course of self-education. By the 1830’s he was producing pieces for newspapers and hort journals and in 1841 his first book, *A Treatise on the Theory and Practice of Landscape Gardening, Adapted to North America, met with great success. It was the first book of its kind published in the United States.

Downing continued to write on the importance of linking landscaping and architecture and was well thought of in the industry. What really put him on the public gardening radar was a book he and his brother Charles wrote. The 1845 book, The Fruits and Fruit Trees of America, was the most complete one of its kind to date and led to Downing’s becoming the editor of a new periodical, the The Horticulturist and Journal of Rural Art and Rural Taste. The journal came to be his strongest influence on society and operated under the premises of horticulture, botany, entomology, pomology, rural architecture, landscape gardening, and ideas dedicated to public welfare, specifically public parks and what we now call “open space”. As an example he argued for a New York City park, which in time became Central Park, in this journal. It was also in this publication that Downing repeatedly pushed for state agricultural schools.
He held the position of editor until his death in 1852.

Downing was greatly influenced by the British “picturesque” landscape theories of the era. By the time he published the second edition of his Treatise he was a firm believer in the advantages of the picturesque landscape movement. He embraced the use of local landscape features especially “the raw materials of wood, water, and surface” and, when possible, the blending in with the local terrain instead of creating an artificial, out-of-place one. He became the mid 19th century champion of natural style landscapes and helped steer American gardeners away from the more formal, geometric lines that had dominated the 18th and early 19th centuries.

As an editor, Downing repeatedly addressed the importance of urban and suburban public gardens and parks. He felt such spaces would aid in the fostering of moral and civic virtues in the American public. In the October 1848 Horticulturist editorial “A Talk about Public Parks and Gardens,” Downing wrote that public parks would play an important role “in elevating the national character.” He also believed interacting with nature had a healing effect on mankind, wanted all people to be able to experience nature and felt city parks were vital in helping maintain a healthy community.
Downing had a wide audience through his books and editorials in the Horticulturist but his influence went beyond the readership of his publications. Private and public gardens and city parks that proliferated through out the USA during the mid 1800’s owed their existence to his ideas.

Downing did much more than this blog post will discuss so let’s move on to the plant.

The genus **Downingia is named after Andrew Jackson Downing. It contains 13 annual plants which are native to the western USA and Chile. Commonly known as calico flowers, they are noted for forming large displays of small colorful blooms around seasonal or ephemeral pools of water. Interestingly each pool will usually only host one or two species of Downingia even in areas where multiple species exist.
It’s a member of the bellflower family and the plants are 3-10″ tall.  Flower size varies but each flower has five corolla lobes or petals. The two upper petals are smaller than the three lower ones. Coloration is mainly blue/purple/pink with a little white, yellow, and black.
Downingia must cross-pollinate. To prevent accidental self-pollination, the flowers mature in stages, they go from male to female. This change is time coordinated across each patch of flowers. How this is done is still unknown.
The species is pollinated by native solitary bees.

*https://openlibrary.org/works/OL1471543W/A_treatise_on_the_theory_and_practice_of_landscape_gardening?edition=treatiseontheory01down

**https://www.wildflower.org/plants/search.php?start=0&pagecount=10