THE BEST TREES FOR MEMPHIS
(AN ODE TO COLUMNAR DECIDUOUS TREES)
Though a good horticulturalist can be successful planting any time of the year, the best time to plant trees and other woody plants in the Memphis area is in the fall. So, it’s time to start contemplating what you’re going to plant this fall! (This is the first of a series of blog posts I’ll be doing on fall gardening activities over the next few months.)
Trees are categorized in many ways. Aesthetically, trees are most often categorized by size, shape, and whether they are deciduous (meaning they lose their leaves in winter) or evergreen (meaning they keep leaves year round). The size categories are usually small, medium, or large, defined best here, https://www.arborday.org/trees/righttreeandplace/size.cfm, while canopy shape is defined best here: https://extension.tennessee.edu/publications/Documents/SP531.pdf. The tree sizes and shape I advocate most for in urban environments, which usually have smaller yards, are small to medium sized trees with columnar shaped (also called fastigiated) canopies.
Columnar trees have a strong vertical form and are often six feet or less in width. The most well-known columnar tree forms are probably arborvitae and Italian cypress, both commonly associated with Mediterranean landscapes but widely used in Memphis. For example, Presbyterian Day School has a row of small arborvitae, about 8 feet tall, on the south end of one of its playing fields bordering Central Avenue. Then, there is a row of 3 very tall Italian cypresses, over 30 feet, in midtown on Evergreen, a couple of blocks north of India Palace Restaurant. These two examples are both evergreen.
But, lesser known, and I think under-utilized until the last few years in Memphis are columnar deciduous trees. We often think only of deciduous trees as large shade trees, except perhaps for Japanese and other maples or the widely over-planted crepe myrtles. Customers rarely specifically request a columnar deciduous tree at our nursery. In fact, just as new wine drinkers often prefer sweet white wines before maturing into cabernets and merlots, inexperienced gardeners gravitate towards things that are covered in blooms part of the year or evergreen, preferably both, fearing the bareness of deciduous plants in winter and not appreciating the texture of mere leaves without flowers.
One big advantage of deciduous columnar trees over evergreens like arborvitae and Italian cypress is that they tend to have fewer problems. The evergreens prefer the subtly different Mediterranean climate rather than ours, are sensitive to both under-watering and over-watering, and too often get bag worms and other pests, particularly in early summer. In contrast, well-planted deciduous columnars are relatively maintenance and pest free, needing only the occasional pruning of dead branches. Without leaves in winter, a sudden ice storm is less likely to damage them too. Most importantly, as a gardener matures in her appreciation of the life cycle of plants, she comes to appreciate the changing shape and color of leaves over the course of spring, summer, and fall, and the architecture of bare branches in winter.
He who marvels at the beauty of the world in summer will find equal cause for wonder and admiration in winter…. In winter the stars seem to have rekindled their fires, the moon achieves a fuller triumph, and the heavens wear a look of a more exalted simplicity. ~John Burroughs
So, increasingly, the landscape industry and home owners are realizing that medium and small deciduous trees in general, including columnar cultivars, are better alternatives than columnar evergreens. Moreover, they are realizing that smaller trees are better for the close confines of modern urban environments than the old standard unimproved shade trees like oaks, elms, gingkoes, and tulip poplars that were widely planted in Memphis during the twentieth century. Indeed, if you have ever had to contend with a large old specimen of a deciduous shade tree too close to your home, you know how challenging they can be. The roots can rip apart foundations and sewer pipes. Leaf removal under the canopies of large old deciduous trees in the fall can be an enormous undertaking. And, worst of all, falling limbs or entire falling trees, weighing tens of thousands of pounds, can destroy property and cause human injury or death. To make matters worse, tree removal of a large deciduous tree that has been diagnosed as too unsafe to keep in place, can cost $15,000 or more.
Consider, for example, a mature oak tree, inexplicably planted 15 feet from the rear of an east-facing home. The tree has been diagnosed with an incurable fungal problem, its roots have largely rotted, and its leaves are only green because of stored photosynthates. It remains erect only because it weighs 70,000 pounds and is like a nail whose point has been tapped into the ground. Eventually, because this is Memphis, a straight-line wind will come along from the west, push the tree over, and flatten the home, destroying it and everything in it. A wise homeowner, faced with this information may feel they have no choice but to pay to remove it at a cost of as much as 10% or more of the home’s value, enough money to buy a new car or increase the size of the home. Likely, this tree was not “planted” but rather was a volunteer, allowed, maybe even encouraged by a new homeowner decades before, a homeowner who likely felt very proud that he had not had to pay for it, regarding others who had designed intentional landscapes as spendthrifts.
But then, there are those who over-react to this problem, removing all trees from their property, leaving only foundation shrubbery and turf grass, with no shade, like the homes in new mid to low grade subdivisions. This approach has its problems too. There is no shade without trees so more energy is needed to cool the home in the summer and the benefit of deciduous trees that mitigate carbon emissions is entirely lost. Further, for whatever reason, humans find the close proximity of trees comforting. They have an inherent attraction for us and we do not find a landscape wholly devoid of them attractive or as appealing as a yard with one or more well-placed trees on it.
Hence, the arbor market is now producing more manageable small and medium-sized columnar cultivars of old standbys. They tuck nicely into courtyards, make for beautiful allees, and form inspiring focal points in corner beds. For greater impact they can even be clustered in trios! Here are some of my favorites from our growers:
Columnar European Hornbeam (Carpinus betulus fastigiata) has been around for a while, the Frans Fontaine cultivar of columnar European hornbeam being my favorite of the various cultivars (a cultivar is a variety of tree discovered by a grower deliberately looking for variations within a population of trees and then propagating, usually by cuttings, that tree because of its atypical but desired qualities.) The ‘Frans Fontaine’ cultivar tends to get about 25 feet tall and 6 feet wide, tucking into the corner of a foundation bed nicely or making a nice focal point in a larger bed. They also look great in a formal row. I first became aware of this tree when the Dixon Garden, under the direction of Dale Skaggs, planted an allee (a walkway or avenue lined on both sides with trees) of them a few years ago. With alternate oblong-ovate leaves with rounded base and acute tip, pale green in spring, dark green in summer, and pale yellow in the fall, the canopy forms a dense oval of overlapping leaves that flutter in breezes and come across like an impressionist painting from even short distances.
Though ‘Frans Fontaine’ gets larger in other climates, in our climate it tends to be more restrained, seldom getting much larger than 25 feet tall and 6 feet wide. Unusually, the tree is tolerant of extreme pruning, some horticulturalists pruning the limbs all the way back to the trunk once each year to keep it even narrower than it already is. It is not infrequently used as a screen or hedge, similar to how english hornbeams are used at one of Martha Stewart’s homes, as described here:
Goldspire Ginkgo (Ginkgo biloba ‘Blagon’) is a new cultivar of an old favorite. Ginkgos have long been regarded as the oldest species in continuous existence on the planet, in either kingdom, with some fossils of ginkgo leaves as much as 270 million years old. They have unique fan shaped leaves leafing out pale green in the spring, darkening, and then turning a striking fluorescent yellow in the fall just before leaf drop. With a large genome of over 10 billion DNA nucleobase letters and over 41,000 predicted genes (the human genome has around 3 billion) the plant has excellent disease resistance and general all-around toughness, having lived through more existential threats than any other plant alive. Though the species can get over 100 feet tall, the Goldspire cultivar (‘Blagon’) tends to be much smaller, 15-20 feet tall and 5-6 feet wide.
Because the cultivar was only introduced in 2010, coming from France, the tree is hard to find. I have sold a handful to customers in Memphis but I don’t know where they are planted. So, just like any new cultivar, it is a risk, since there is not much history to go on. But, given the success of other ginkgo varieties and cultivars, and the benefits of an unusually small cultivar, perfectly sized for tight urban confines, it seems worth the risk. If it proves itself over the next couple of years, it may replace ‘Frans Fontaine’ as my favorite columnar tree. If you want this tree, be sure to email us right away to get on the waiting list for it, as we are only expecting to be able to get a few this fall.
Persian Spire Ironwood (Parrotia persica ‘JL Columnar’) is an even newer cultivar than Goldspire Ginkgo! Discovered by John Lewis of JLPN Nursery in Salem, Oregon in 2013, it is an unusually slow growing ironwood, upright and columnar in shape, topping out at under 15 feet. But, the most unique thing about this tree is its foliage, especially in fall, when it takes on purple, orange, and red hues, sometimes all on the same leaf, and holding onto the tree for quite awhile after the color changes, before fall abscission (leaf drop). Read more about this great new cultivar on the the Pacific Northwest International Society of Arboriculture site: http://pnwisa.org/2017/06/persian-spire-upright-ironwood-parrotia-persica-jl-columnar-p-a-f/
As of this writing, Urban Earth has sold a total of 3 of this plant and has one in stock, all in 15 gallon containers, about 6 feet tall. 2 have been planted at an apartment complex across from Ardent Studios on Madison and one has been planted at a private residence. We hope to get a few more this fall but don’t expect this cultivar to be easy to get for a few years. There is no question that anyone who planted one of these trees this year would have one of the rarest trees planted in Memphis, for at least a few years.
Slender Silhouette Sweetgum (Liquidambar styraciflua ‘Slender Silhouette’) is the tallest of all of the trees referenced in this article. Growing as tall as 60 feet and as wide as four feet, it more commonly tops out at 50 feet with a width of 3 feet. It is also the quickest growing. Though it is used in landscapes in Memphis in a variety of ways, one of the best ways I have seen it used is as a corner piece to soften the edge of a two story home in Germantown. Read more about this tree here: http://www.hortmag.com/plants/plants-we-love/slender-silhouette-sweetgum
Lindsey’s Skyward Bald Cypress (Taxodium distichum ‘Lindsey’s Skyward’) has been around long enough, at least 16 years, to prove itself to be a great success in the Memphis area. Though it is a conifer, it is, in fact, deciduous, but tolerating wet feet better than most. A dwarf, it gets up to 20 feet tall and 6 feet wide. A truly lovely tree, though this author does not have much experience with it, it is one of Greg Touliatos’s favorites.
Mushashino Zelkova (Zelkova seratta ‘Musashino’) was named the “2016 Urban Tree of the Year” by the Society of Municipal Arborists. Meant primarily to be a tough street tree, it can also be used, like all columnar trees, as focal points in the landscape, as allees, and as screens. Though too new of a tree to know for sure, it is said that it “has the genetic potential to reach 45 feet in height and 15 feet in width at maturity,” with orange/red leaves in fall, with leaves in an oval shape and serrated at the edges, reminiscent of a hornbeam’s leaves. Read more about this new tree of great promise here: https://www.amerinursery.com/plants/sma-announces-its-2016-urban-tree-of-the-year-zelkova-serrata-musashino/
Regal Prince Oak (Quercus x warei ‘Long’ REGAL PRINCE) is perhaps the fattest of the trees described in this article, though not the tallest, getting up to around 45 feet and 20 feet wide near maturity. The older leaves turn a beautiful red in the fall after the tree has matured for a few years in the landscape. Look here to find a good concise history of this tree, well proven in the Memphis area: https://www.uaex.edu/yard-garden/resource-library/plant-week/quercus-xwarei-oak-regal-prince-01-22-2016.aspx
Arnold Tulip Poplar (Liriodendron tulipefera ‘Arnold’) is an excellent cultivar of our state tree. It is a compact solution for anyone who wants to show their loyalty to Tennessee but has too small of a yard for a full size tulip poplar. Most commonly, you can expect this tree to mature at around 25 feet tall and 8-10 feet wide in the Memphis area, though it might get taller in other parts of the world. Its blooms are yellow-green, tulip shaped, beginning in late spring through the summer.
The author, John Jennings has been manager of Urban Earth Garden Center since June 1, 2016. Before that he was a self-employed landscaper for 8 years, having previously worked as both a real estate lawyer and a drug counselor in previous lives. He grew up in the South Carolina low country, learning to garden in the fertile soil of Copes Island, a small barrier island near Beaufort, in Jasper County, the famed land of Pat Conroy. He was taught the basics of planting by his step-father, Wade, his mother, Melissa, and his father, Karl. Though both of his parents grew up in Memphis, and he spent vacations visiting his maternal grandparents, Richard and Diana Allen in Memphis, he did not become a resident of the city until he finished college in 1994. He left South Carolina at the age of 14 to attend The McCallie School for Boys, in Chattanooga, Tennessee, graduating in 1990, before getting a degree in English from the University of Richmond, in Virgina,in 1994, finally graduating from the University of Memphis Law School in 1997. He has a 10 year old son named Henry.