BIO Blog

Today we'll discuss bio plants, those that are deemed of "botanical interest only." These trees and shrubs are not boring, not at all – at least to me, but certainly you will not find many (or any) of them in your local garden center. There are various reasons for their scarcity, like difficulty to propagate, or that they get too big, or simply because their cousins display larger flowers or better forms, or, for no apparent reason.

Tetracentron sinense

Tetracentron sinense (Szechuan form)

Tetracentron sinense is one such bio tree. It will make a medium-size tree with a resemblance to Cercidiphyllum. I recently saw two types of it at the Rhododendron Species Foundation in Washington state. One was the Szechuan form which I preferred over another from a different province.

It is appropriate, I suppose, that this monotypic Chinese species would be planted in Washington, since the fossil record indicates it once grew there, as well as in Alaska, and even in Iceland. The flowers are not showy, they are small wind-pollinated organs that dangle in slender catkins. In a woodland setting Tetracentron will grow narrowly to fifty feet or more, but will display a more broad canopy in full sun. They require a moist, but well-drained soil, and are hardy to USDA zone 6. Tetra is Greek for "four," but I don't know what centron is referring to; I suppose some central element of the flower. The common name for Tetracentron in China is "Shui Qing Shu," but that's Greek...er, Chinese to me.

Euscaphis japonica

Euscaphis japonica

Euscaphis japonica

Euscaphis japonica

Euscaphis japonica

Euscaphis japonica is commonly known as the "Korean Sweetheart Tree," as if anything nihon-jin would have fondness of anything Korean, but its common name is due to the fact that it was originally introduced into America by J.C. Raulston's 1985 collection in Korea. Don Shadow, a Tennessee nurseryman, coined the "Sweetheart Tree" name because of the heart-shaped seed capsules that turn red in autumn, then open to reveal black seeds which stay attached for a while – a most ornamental effect. Branches are stocky and horizontal, and the thick leaves are glossy green – Euonymus-like – and turn to orange in the fall. The winter trunk is attractive, a slightly furrowed gray with purplish striations. Euscaphis japonica is hardy to USDA zone 6, and has a place, I think, in most any garden. I don't know why we don't see it used more often; maybe because it doesn't readily root like the Euonymus, and I know of no rootstock that it could be grafted onto. So, raising little sweethearts from seed is the (only?) option, and I'll have to find time for that project this year.

Euonymus species

Speaking of "Euonymus-like," the true Euonymus, or "Spindle Trees," consist of about 175 species of evergreen or deciduous small shrubs and trees. The common name is due to the making of spindles from the wood of some species for spinning wool. The tree species are noted for ornamental red fruits in autumn, and the deciduous species are famous for flaming fall color. Garden snobs will insist that the genus is overused, but heck, it is a tough group of plants that survives in most conditions. I'll admit that I can't stand the bushy and creeping variegated cultivars...or should I say that I can't stand the factories that crank them out by the millions? When times were good, these nursery-factories made tons of money on the easy-to-produce crop, but in recent times scads have gone up in smoke...and good riddance to the plants, and to some of the companies as well.

Euonymus phellomanus

Euonymus phellomanus

I will champion a few of the tree-like Euonymus species however, but while I enjoy them immensely, I've never been able to even give them away, let alone sell them. Euonymus phellomanus is the "Willowleaf Spindle Tree," and its leaves do resemble the "Willow Oak," Quercus phellos. It is also called the "Cork Tree" as the ridged trunks can break off into corky plates on mature trees.  While it has been recorded in the wild in Connecticut and Massachusetts, it is actually native to woodland forests in China. Fall color isn't so intense as on some spindles, but rather is a more subdued pastel of pinkish-red, and the fruits are also pink. The species is hardy to -20 degrees F, USDA zone 5, and is well-worth growing if you can find it; but you won't from me, as I gave up years ago on the mission of converting the public, via retail outlets, to obscure Chinese Euonymus species. By the way, avoid eating the toxic fruits, unless you are one of those plant-factory persons, now on hard times and can see no way out.

Euonymus oxyphyllus

Euonymus oxyphyllus ranges from China, Korea to Japan, and is also hardy to -20 degrees F. Though the leaves are said to be edible, I'm sure not going to try them, especially since, yikes!, the plant has been used in gynecological applications. Oxy is Greek for "sharp, acute, pointed or acid," so the leaf is described as one of the above, hence the species name. An oxymoron is a combination of opposites, literally meaning "sharp-dull." The Greek word oxygen comes from oxus meaning "acid," and gennan meaning "generate," because it was believed that all acids contained oxygen. The Atomic Number of the element oxygen is 18, and you should know that it comprises 21% of the atmosphere...but I certainly digress. "Digress" is from Latin digredi, to "go aside,  to depart;" sorry, but regular Flora Wonder Blog readers already know about my obsessive etymological hobby. Etymology: from Greek etymon for "true sense" and logia for "study of." Ad infinitum to me, ad nauseam probably for you.

Euonymus sieboldianus

Anyway, back to a final spindle species, the Japanese Euonymus sieboldianus, which was named for Philipp von Siebold, but has nothing to do with his anus; nor does it Hamilton's, as it is also known as Euonymus hamiltonianus ssp. sieboldianus. Fruits are pinkish-red, but I'm mostly attracted to the winter trunks. Euonymus is in the Celastraceae family, and the Euonymus name originates from the Greek eus for "good" plus onoma for "name," i.e. an "auspicious or honored name." In Latin times that's probably a sarcastic sense, since the Euonymus flower was thought by Pliny to be a forecast for pestilence. Last fall and winter was most pestilent in my opinion, as neighboring nurseries burned thousands of Euonymus, including their bark-based-media with petroleum fertilizers and poisonous pesticides.

Sorbus commixta

Sorbus commixta

Sorbus commixta is the "Japanese Rowan," and is native to northern Japan, Korea and eastern Siberia. It grows into a small to medium-size deciduous tree with bright orange-red berries in early autumn, followed by outstanding yellow, and orange-to-red fall color. Sorbus is from a Latin word for "service," as the tree has many uses, similar to a species of birch, Betula utilis, because its wood is "useful." The genus is also commonly known as an "Ash," for its resemblance to the Fraxinus genus. The word Rowan is commonly used for Sorbus aucuparia, the "Mountain Ash," and is derived from the Old Norse name, raun, for a tree. It is a stretch then, to use an old European common name for an eastern Asian species name. The very first tree that I encountered upon entering Kew Gardens in London for the very first time, was Sorbus commixta, and all autumn photos above are from that date.

Magnolia wilsonii

Magnolia wilsonii is a wonderful species, named in honor of the great plant collector E.H. "Chinese" Wilson, but one I've never seen offered in an Oregon garden center. Its scarcity is no doubt due to pendulous flower cups which bloom amidst the foliage, while the public seems to prefer the more gaudy precocious (i.e. blooming before foliage appears) species. But don't sell Magnolia wilsonii short, and you won't if you view the flowers from beneath, as the photo above illustrates. The pendulous tepals are the purest white, and they hide the crimson stamens unless you lift the flower up or view from beneath. Sadly, Magnolia wilsonii is on the IUCN Red List of Threatened Species.

Leucothoe keiskei

Leucothoe keiskei

Leucothoe is an ericaceous, evergreen shade-loving shrub from North American and Japan. The 

genus is known in America as "Fetterbush," as are other genera, for supposedly they impede walkers.
Fetter is something that restrains, from Old English feter, from Old English fōt for "foot." Leucothoe was chosen as the genus name in the late 1700's, though I don't know why the King of Babylonia's daughter Leucothoe would have anything to do with the plant, and certainly it could never survive in the Middle East. The Japanese species keiskei is the most choice of the group, the most refined, and the delicate arching shoots remind me of flowing water. The rich mahogany-red winter leaves are spectacular, but in a subdued, earthy way. Ten years ago a cultivar of keiskei, 'Royal Ruby', came on the scene, I think from England. After growing it a couple of years I called my original supplier, for the growth habit and leaf shape of 'Royal Ruby' were noticeably different than my keiskei. Perhaps it was a hybrid, which would be fine, as long as I knew the identity. Ultimately I threw them out, especially since the supplier said "Well, you win some and you lose some." No mention was made about returning any of my money. If you view the images of Leucothoe keiskei online, you'll easily see that some resemble my photos above, and some certainly do not.

Acer nipponicum

Acer nipponicum

You definitely will not find an obscure Japanese maple species, Acer nipponicum, at your local garden center, but still it is one of my maple favorites. Leaves resemble Acer tegmentosum, but are more brownish green, and feature a more rugose surface than tegmentosum. Fall color isn't spectacular though, but in some years it can be pleasantly yellow with brown margins. The species name is an old word for something from Japan, but today Japanese people use Nihon instead of Nippon to refer to their country, and I think "Nippon" carries a derogatory connotation. When I was young and insensitive I would tell a sophomoric joke: "What do you do when it's a little nippy outside?" The answer of course "is to let him in." Ha, Ha. But since marrying an elegant Japanese woman I have improved my ways.

Acer nipponicum is rare in collections because the cuttings are difficult to root (I've tried and got 0%), and since it is in its own isolated group, there are no apparent rootstocks to use (also I've tried). All of my trees are seedling grown, and those are rarely offered. It is hardy to -20 degrees, USDA zone 5.

Acer pentaphyllum

Another interesting maple species, Acer pentaphyllum, is of Chinese origin, and it is threatened in the wild. I used to grow a lot of them, and I thought that at one time I had more in my nursery than were left in the wild. I had no genetic diversity in my collection, as all trees in America (at the time) came from one tree grown at the Strybing Arboretum in San Francisco. This five-lobed species can be propagated by rooted cuttings in summer under mist, from seed, and by grafting onto various rootstocks, such as Acer rubrum.

Acer pentaphyllum

Cannabis sativa, legal in Washington state

Acer pentaphyllum presents a light "airy" appearance, due to very narrow light-green lobes. Fall color can be straw yellow in some years, or orange-to-red in other years, and this phenomena has occurred on the same tree. You can always detect a stoner around Acer pentaphyllum, because you get comments like "Dude, can you smoke it?", referring to Cannabis sativa, a lookalike. Acer pentaphyllum is hardy to only 10 degrees F, USDA zone 8. I once thought that using hardy Acer rubrum as rootstock might boost pentaphyllum's hardiness, But in a cold winter the top died completely, while the lower rubrum rootstock bursted with new shoots in spring.

Enkianthus serrulatus

Enkianthus serrulatus

Enkianthus campanulatus cultivars are commonly planted by discerning gardeners, while Enkianthus perulatus, a much more slow-growing species, is considered an even more elevated garden choice. Enkianthus serrulatus is a Chinese species that has never occurred in an Oregon garden center to my knowledge, but I was fortunate to be given a plant by Roger Gossler, owner of a specialty mail-order nursery in Oregon. Flowers are larger than with species perulatus, and they are a creamy-white color. In my opinion, the large serrulatus shrub is worth growing for its fresh green foliage (best in partial shade) and for exciting oranges, reds and purples in autumn, even if it never bloomed. For the readers who wish to go into more depth on the Enkianthus genus, I encourage you to see Enkianthus in cultivation in the June 2011 edition of The Plantsman by Clark, Hsu and Camelbeke.

Picea likiangensis

Picea likiangensis

Tiger Leaping Gorge on the Yangtze River

I would be remiss to exclude some coniferous species as worthy specimen trees, if only you could find them to buy. Picea likiangensis is the "Chinese Red Cone Spruce," so named because it comes from the Likiang region in Yunnan. I've seen it in the wild near the Tiger Leaping Gorge on the Yangtze, and it forms a compact pyramidal tree with sharp glittery blue-green needles. In spring cones rise erectly and are a stunning crimson-red, then by summer they droop downward and are a wonderful honey-brown color. The species is attractive, more-so than the larger-growing Picea abies, I think, and appears something like a cross of Picea abies with Picea glauca. Though growing to a medium-size tree, I think that anyone seeing it in cone would certainly want to have it.

Picea polita

Picea polita

Abies pindrow

Juniperus pingii

Juniperus pingii

This likiangensis species means a lot to me personally because, as I've said, 1) I have seen it in the wild, 2) it is a uniquely beautiful species, and 3) it helped to define the Buchholz niche early in my career. I started in business with a love for trees, but I had little experience to grow and sell them, and I figured I couldn't compete with the large operations growing thousands of common, easy-to-produce plants such as Mugo pine, Alberta spruce, arborvitae and the like, so I operated at the fringe of horticulture by providing species that the nursery mainstream had never heard of before. And I found that there was a market indeed. The American nursery "trade" had for years chugged along without Picea polita, Abies pindrow, Juniperus pingii and some of the plants featured above. And maybe I've had more fun horticulturally in my career than the plant-factory boys.

Sinowilsonia henryi

I was going to include Sinowilsonia henryi in this bio blog, but I found that I didn't have a photograph of it. My interest in this Hamamelidaceae member was really due to my admiration of the two principles in the name: E.H. Wilson and Augustine Henry, both of whom spent years in the Chinese interior when the going was rough. That aside, the reason I didn't have a photograph was because there has never been a scene to record. Like Oakland, California, there's no there there. As dry old Krussmann says in his Manual of Cultivated Broad-Leaved Trees and Shrubs concerning Sinowilsonia henryi: "it is not particularly meritorious." But I've found room in my collection for this plain-Jane species anyway, because that is who I am.

"Talon, thank you so much to grow Sinowilsonia henryi."