Friday, October 7, 2016

The Year in Trees

In the last Flora Wonder Blog I mentioned Dr. Kim E. Tripp, the woman who advised me to visit California's White Mountains to see the Pinus longaeva in their native haunt. At the time she was with the JC Raulston Arboretum in North Carolina, but now she is Director of the New York Botanical Garden. I will be in New York next week, so I hope I can see her again.*

*Yikes! I stumbled upon her “March” appointment to the NYBG Directorship on the internet a short time ago, which was news to me. I emailed the garden to see if she would be around, but received the reply that she left the position “about ten years ago.” So I was reading an old post it seems; I must be more careful about internet news, err...olds. Nevertheless I will complete this blog based upon her book.

While Dr. Tripp was at the Raulston garden, she and the late JC Raulston had a book published, The Year in Trees, subtitled “Superb Woody Plants for Four-Season Gardens.” The book is 21 years old now, which is a long time in modern horticulture. According to the jacket, “The Year in Trees is for gardeners, designers, and nursery people who wish to look beyond the 'old standards' of trees, shrubs, and vines that dominate our landscapes.” One of Raulston's theories was that 40 shrubs and trees make up 90%-plus of the landscape plantings in any given region of the United States, so the book's purpose is to present 150 “plant portraits” based upon weekly profiles written by Dr. Tripp as part of the arboretum's outreach activities. These are plants that “deserve a chance in our gardens.” The publisher – Timber Press – calls the work an “international book” as all of the plants “have been evaluated for their usefulness as good, reliable garden plants.”

Acer triflorum
Oxydendrum arboreum 'Chameleon'

Sometimes a species is described as garden-worthy in and of itself, such as with Acer triflorum and Oxydendrum arboreum, but most of the 150 mentions cultivars as well. That's when I say that 21 years is a long time in horticulture, for I would be bankrupt if I was growing most of the cultivars today. I wonder how Dr. Tripp would re-write the book, if there would be any changes at all.*

Xanthocyparis vietnamensis
Xanthocyparis nootkatensis

* There would probably be nomenclatural changes, such as Chamaecyparis nootkatensis becoming Xanthocyparis nootkatensis, but I don't know about her other recommendations.

Xanthocyparis nootkatensis 'Green Arrow'

Xanthocyparis nootkatensis 'Laura Aurora'

Xanthocyparis nootkatensis 'Sparkling Arrow'

Speaking of nootkatensis, Buchholz Nursery rates a mention for my introduction of 'Green Arrow' which was considered “newer” in 1996. I didn't discover 'Green Arrow' – that would be the late Gordon Bentham of Victoria, B.C. – but I did rescue young starts from a bankrupt and dissolving Canadian nursery that he worked for, and had I not, the world would never have known it. Dr. Tripp describes it as having “lighter green foliage” than the species, but I would call its color gray-blue more than light green. She also mentions the variegated form 'Laura Aurora' which I named for my daughter. I shouldn't have because we learned over time that it reverts and it was dropped from our propagation program long ago. Another cultivar is the old 'Variegata', but it too reverts, and it has effectively been replaced with 'Sparkling Arrow', a selection that arose from a branch sport on one of my original 'Green Arrow' trees.

Other than the brag above, I think nothing in the book has a direct connection with me, and I'll further confess that, after buying the book, I've never picked it up since my initial purchase and quick page-through. That is not an indictment of the book, but rather of my attention span, and I conclude that now I find the “portraits” far more interesting and there are many more depicted plants that I can relate to and now also admire.

Feijoa sellowiana

One such is Feijoa sellowiana, the “Pineapple Guava” from South America, and Ms. Tripp asks the question: “Is guava a tropical fruit or a unique landscape ornamental?” The answer is: “It is both,” and furthermore describes it as “an exotically appealing shrub whose dramatic flowers could be the subject of a Georgia O'Keeffe painting.” I agree when she writes that it is a “handsome evergreen shrub with unique character that would warrant a place in many gardens even if it never flowered, but the blooms...are such treasures that they steal the show from the plant's other attributes.” Ms. Tripp enthuses that the flowers “nearly defy description,” that “A ring of snowy white sepals arches gracefully back and down to reveal velvety magenta petals surrounding a tuft of cherry-red stamens that are each dusted with bright golden pollen.” A plant cannot get more erotic than Georgia O'Keeffe would surely have known, but I doubt that the painter ever saw the guava. My Brazilian intern, Rodrigo, knows the plant and that it bears yellow berries with a pineapple-like taste. It is reliably hardy to only USDA zone 8 (10 degrees F), but with a little protection it can survive in North Carolina's – and my – USDA zone 7 (0 degrees F) gardens.

Magnolia denudata


Dr. Tripp waxes poetic throughout the book, a trait that is not too common among her fellow academics, when she describes Magnolia denudata's flowers unfolding as if “some garden magician had persuaded pastel waterlilies to flower on the branches of a tree.” The specific name, denudata, is due to the flowers blooming precociously – or “nudely” on leafless branches, and according to Tripp the name Magnolia was given by the “famous father of botany, Linnaeus, for a French botanist, Pierre Magnol.” With that statement I must protest, however, and while we should give Linnaeus his due for being the nomenclatural father of botanical classification, the true Father of Botany must be Theophrastus, the 3rd Century BC Greek polymath and cohort of Aristotle – some would say A's student and follower – but others would describe him as Aristotle's equal in the natural world. I'll save Theo's biography for another time and allow that Linnaeus – the Latinized version of Linne which he bestowed upon himself – was a major player in the systematic understanding and ordering of our natural world. I nit-pick of course for the sake of the blog, but I would have been fine if Tripp called Linnaeus a “Father of Botany” instead of the Father of Botany.

Juniperus squamata 'Blue Star'

Lest the Blog bogs, lets turn to another Raulston-Tripp plant, Juniperus squamata, which is commonly known as the “Singleseed juniper.” However, I have always known it as the “Flaky-bark juniper,” while the “singleseed” designation is due to the fruiting habit of the species. Who cares now (?) since the damn species is definitely out of favor. I am surprised that it was even in favor, let alone on two horticulturalists' top 150 of all landscape plants. Dr. Tripp describes it as a “cool blue shrub that holds its soothing color through all four seasons,” but allows that “the wild species is almost never seen in cultivation.” I know why, for I have encountered it in western Nepal, and it's because it is one of the most ugly trees I have ever seen. Portions of the foliage, under any kind of stress, can turn brown which persists on the tree. The foliage, even when alive, is short and prickly and in Oregon the species' cultivars develop a crud – I don't know what it technically is – that leads to light-brown-dying stem scales which are most unornamental. Perhaps the best known of squamata's cultivars is 'Blue Star' – a great name and a great plant for the first six or ten years...before it flops open and develops its brown portions. I don't recall seeing even one specimen of J. squamata at the JC Raulston Arboretum on my visit two years ago, and I wonder how they would evaluate it today.

Euscaphis japonica

Euscaphis japonica makes its appearance in the summer section of The Year in Trees, though I consider it to be in its prime right about now. Still relatively unknown in the trade,* it was brought to America from Korea in 1985 when JC Raulston was part of the United States National Arboretum collection team. It forms an upright deciduous tree – at least at Buchholz Nursery – and since many plantsmen don't know it they would suppose that it is an Euonymus. Don Shadow of Tennessee bestowed the common name of “Korean sweetheart tree” due to the pink red lips-like fruit which opens now to reveal a tiny black berry. The generic name of Euscaphis is derived from Latin eu for “good” and Latin scapus for a “scape,” which is usually a leafless stem. Dr. Tripp describes the plant as “remarkably tough, growing and thriving through droughts and wet periods in some of the worst clay soils the southeastern Piedmont can dish up.” I wouldn't know because I've always kept my trees in the greenhouse...just in case.

*I looked in the Hillier Manual of Trees and Shrubs for more information on Euscaphis japonica but it is not even included.

There were a few plants in the top 150 that I have never heard of before, one being a “Leatherwood,” Cyrilla racemiflora. It is a deciduous or evergreen shrub “native to the swamps and wet places of the southeastern United States and farther south into South America, but in the landscape it is tolerant of a range of conditions,” according to Dr. Tripp. She considers it an “architectural plant” and laments that it is scarce because “the customer is always in the garden center in the spring, picking out azaleas. We must start asking garden centers and nurseries for plants that offer architectural quality as well as showiness...” Well, twenty one years later I don't think the situation has improved. If I was to list Cyrilla nobody would order any, which means that I might grow one in the Arboretum only. Personally my trees must feed my family and I am not on a mission to convert anyone. That's the job of the JC Raulston Arboretum, and good luck with your efforts.

Cunninghamia lanceolata 'Glauca'

I was surprised to see Cunninghamia lanceolata, the “China fir,” in the top 150. I used to grow the 'Glauca' cultivar which with age can make an attractive tree, but when young the cutting-grown starts would flop like side branches for years before sending up a strong leader. Another fault is that the sharp needles can burn in a hard winter and then they persist for a couple of years, making the tree look very scrappy. I know all about “China fir” because my grandmother kept a hedge of it, pruned biannually, and it could look dreadful. Plus, it was difficult to fish the ball out of the foliage – lanceolata indeed! Strangely it was used in a long highway divider in a nearby town, where groups of six were planted, interspersed with oaks and cotoneaster. Where in the world did the highway department find them? Cunninghamia would be the last tree I would use, and they are unsightly at best. But North Carolina contains different soils and a different climate than Oregon, so maybe Dr. Tripp knows best.

Lagerstroemia fauriei

I was not surprised to see Lagerstroemia fauriei on the list, and indeed I saw a beautiful large specimen in the garden of Plant Delights Nursery, not far from the Raulston. I don't particularly like the white flowers of the species, but in Delights' cramped garden all you see is the amazing trunk. L. fauriei is native to the mountains of Japan and therefore is more hardy than L. indica, and best of all it is more resistant than indica to powdery mildew. Dr. Tripp writes, “One of the most memorable garden experiences I have ever had was to come around a bend in the path at the North Carolina State University Arboretum to catch the rays of the setting sun as they lit up the trunk of 'Fantasy' Japanese crape myrtle. The cinnamon bark glowed orange and crimson as if on fire...” I don't grow L. fauriei, but if I ever saw one at a garden center I would certainly purchase it. Lagerstroemia was named by Linnaeus for the Swedish merchant Magnus von Lagerström who supplied Linnaeus with plants he collected. The specific name fauriei honors Father Urbain Faurie (1846-1915), a French missionary and botanist. In Japan the species is known as saru suberi, meaning “monkey slip” due to the smooth slippery bark.

Clerodendrum trichotomum

Clerodendrum trichotomum 'Carnival'

Buddleia 'Tutti Frutti'

Both Clerodendrum and Buddleia make the book, although B. davidii is now considered invasive. The reason I mention them together is because I once planted one next to the other, and I did it to entertain my children. When a Clerodendrum leaf was rubbed it gave off a strong odor of peanut butter, while the Buddleia blossom strongly smells of honey – two odors that every kid knows. Buddleia is commonly called the “Butterfly bush” so I guess that butterflies like to feast on the honey blooms. The genus is easy to grow, though not very attractive out of blossom, but they can die to the ground in Oregon's worst winters. Clerodendrum isn't so great looking most of the year, but redeems itself by mid summer with fragrant white flowers with a prominent red calyx. By fall the calyx develops into metallic blue berries, and a 20-year-old tree might be covered with thousands of them. Neither genera would make my top 150 list, not by a long shot, but they are still fun to have grown.

Fourteen years after the publication of The Year in Trees the same Timber Press produced The Gossler Guide to the Best Hardy Shrubs, and I guess you would call the latter our west-coast version. Roger Gossler lists plants alphabetically, not by seasons, and he gushes about 350 “expert choices for your garden.” Both books are informative and filled with interesting trivia, and even though I forget most of it by the next day, I enjoy being entertained by plant-people who know their stuff.

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