Friday, September 28, 2018

Conifers of Japan

In the book Conifers of California (1999) the jacket cover states that “California is home to 52 native coniferous species; no other state, and, indeed, no other comparably-sized region on Earth contains more conifers...” I've seen all of the 52, but hmm...the most? Hey, wait a second! What about Japan, for that country contains lots of pines, spruces, firs etc.? I went to my Hillier Manual of Trees and Shrubs (2014) because the brief encyclopedic descriptions always list the country or region of origin. I was hoping that the California claim was wrong and that Japan would reign as champion, but alas there are only 38 species listed from Japan.

I have seen and even grown most of the Japanese species, the one exception being Pinus luchuensis. The “Luchu” or “Okinawa pine” is hardy to only 20-30 degrees F, USDA zone 9, so it would be of no use to me.

Nageia nagi

Nyakuoji Shrine, Kyoto

Philosopher's path

But let's take a look at some of the Japanese coniferous species that I do know. One is Nageia nagi, and it's not very hardy either. The evergreen genus is in the podocarp family and it is one of those plants that upon first sight you wouldn't think it to be a conifer. I don't grow it for it would take up valuable greenhouse space, but I have seen it growing outdoors in southern California arboreta. The glossy, lance-shaped leaves make it a good complementary accent for the flower bouquets. Nageia is the Latinized version of nagi, and that is the native Japanese word for the tree, so botanically speaking the name is redundant. In the Nyakuoji Shrine in Kyoto, Japan, there is a nagi tree that is considered sacred. Nagi can mean two things: 1) calm, as in a morning calm, and 2) to cut down, as with a sword. If you pay your respects at the shrine your troubles will be cut away, leaving you calm. The shrine is small and peaceful without many visitors, and it is located at the south end of the Philosopher's path (Tetsugaku no michi), a pedestrian path that follows a canal lined with hundreds of cherry trees.

Torreya nucifera

Torreya nucifera is the Japanese nutmeg-yew, an evergreen conifer native to the southern half of Japan. The genus name honors Dr. John Torrey (1796-1873), an American botanist and co-author with Asa Gray of The Flora of North America, while the specific epithet means “bearing nuts.” Leaves are evergreen and give off a pleasant fragrance when bruised. As a member of the yew family (Taxaceae), the fruit is a single seed covered by a fleshy aril, and it is rich in oil and edible. Known as Kaya in Japan, it was first scientifically described by Engelbert Kaempfer in 1712 and was included in the Linnaeus Species Plantarum in 1753 as Taxus nucifera. E.H. Wilson photographed a large tree in Kyushu, Japan in 1916 which was 28m tall and 5.5m in girth, and could possibly have been 500 years old. Wilson wrote that “the wood is yellowish to pale brown, firm and lustrous and durable in water. It is used for making water-pails and for cabinet work.” The species is probably hardy to USDA zone 6 or 7.

Abies firma 'Halgren'

Abies firma 'Halgren'

Wilson continues about the nutmeg, that “in one place only is it common, and that is on Takao san, a hill some 500 m high, about 27 miles southwest of Tokyo, growing with Abies firma.” A. firma is known in Japan as momi, and that word simply means “fir.” According to Hillier it is a large tree which can reach 40 m or more in the wild. The typical American nurseryman or gardener knows nothing about A. firma, and wouldn't know one if they saw it. It is simply in no demand or availability at American garden centers, but to the horticultural cognoscenti it is recognized as an important species. In many parts of Europe and America it doesn't matter, but in areas of high temperatures (especially at night) and high humidity, A. firma is known to survive when other fir species sigh, falter, then expire. It can take the heat, therefore it is a preferred rootstock to be used for the cultivars of other Abies species in areas such as the miserable American southeast. But even on its own it is an attractive tree and I have grown Abies firma 'Nana Horizontalis' – whether or not that is a legitimate name – and also A. f. 'Halgren' which was a discovery of Gordy Halgren of Peacedale Nursery, where his selection was noted for exceptional vigor and very dark glossy-green needles. We root the 'Halgren' then use it as rootstock for a wide array of Abies cultivars, a process more costly than just buying in other fir seedlings as rootstock. Then we have the arduous task of keeping track of the rootstock used when we advertise and sell a specimen 5-to-10 years later. Remember: employees come and go, and they are never as committed to accuracy and knowledge as the owner. Not one of my current employees – who, still, all nurseries would want to recruit – could answer the question of what is the preferred rootstock for Abies cultivars planted in the southeast USA. TMItoo much information I suppose.

Pseudotsuga sinensis

Pseudotsuga sinensis

Pseudotsuga japonica

Early in my career I was impressed to discover that Oregon's common “Douglas fir,” Pseudotsuga menziesii, had relatives in Asia, in both China and in Japan. My Flora Farm residence is host to two magnificent specimens of the Oregon Douglas fir – huge and well over 100 years old – and underneath them I planted the Asian species, Pseudotsuga sinensis and Pseudotsuga japonica. I would love to see them hybridize – kind of like I did with wife Haruko – but I don't suppose that any recognized crossing will materialize in my lifetime. Maybe at a future date someone will praise old geezer Buchholz for bringing the transcontinental species together. Wow! – like Buchholz was able to score a Chinese and a Japanese wife. What will the offspring look like? the least. I suppose I'm most fascinated with the cones of these species: the Chinese being fat and amber and the Japanese being sharp and dark and narrow and the American being in-between. Anyway, I love Pseudotsuga cones, and though they are “false hemlocks,” the cones are far more impressive than the little things produced on “true” hemlocks. It's too bad that the Scotsman David Douglas, who championed the American Douglas fir, was never aware that related species in the genera also existed in Asia. Of course all the Pseudotsuga originally were classified as pines (Pinus) anyway.

Juniperus confera 'Blue Lagoon'

I keep earlier editions of the Hillier Manual of Trees and Shrubs around to compare with changes in the latest, 2014 edition. In the 1981 5th edition, for example, Juniperus conferta is listed as the “Shore juniper,” a native of Japan and Sakhalin “found on sandy sea-shores.” I was surprised to read that it was introduced by E.H. “Chinese” Wilson in 1915, as you would have thought someone would have introduced it long before. In the 2014 edition we learn that it is now classified as J. rigida subsp. conferta. Hillier has also added a few sentences to the description, calling it an “invaluable ground-cover species,” and uses poetry practically by referring to “dense prickly carpets of apple-green foliage.” Apple-green – I like that. We have a specimen growing in our Blue Forest of J., rigida subsp. conferta 'Blue Lagoon'. I just went out to look at it – hopefully nobody saw me staring at it for five minutes – but I think it is poorly named. I can detect nothing blue at all, only silver and green, but it is a dense mat less than one foot tall and a whopping 51' (15.5 m) wide.

Podocarpus macrophyllus

Podocarpus macrophyllus is the Japanese “Sweet Kusamaki,” an evergreen conifer from southern China and Japan. It is commonly seen in Tokyo, used as a single specimen or effective as a hedge. Careful with children, however, because the purple-red fruits on female plants are poisonous if eaten. When I was young I grew one as a houseplant, and though the species is in the Podocarpaceae family, I knew it as the “Buddhist pine,” and it was purchased cheaply at the grocery store. It is more highly valued in Hong Kong because it is considered a Feng Shui tree, a Chinese pseudoscience* that believes energy forces harmonize individuals with their surrounding environment.

*Superstitio absurdissima.

Larix kaempferi

Larix kaempferi 'Heverbeck'

Larix decidua 'Pendula'

I have been growing Larix cultivars since I began my nursery, but I never really know if the “Japanese larch,” Larix kaempferi, is the correctly identified species or if it is sometimes Larix decidua, the “European larch,” and vice versa. The new shoots of the Japanese are reddish in color while the European's shoots are yellow-to-gray, but in spring I'm too busy to walk around and study the larches. It is confusing, though, to have a L. d. 'Pendula' as well as a L. k. 'Pendula'.

Larix kaempferi 'Diana'

A German nursery woman visited us twenty years ago and she was pleased to see Larix kaempferi 'Diana'. Please because her employer found it in the wild in Germany (1974). “Wait a minute,” I thought later that night, “how could he have found a Japanese species in a German forest?” I saw her again the next day, and demanded an explanation. She reported that Larix kaempferi was commonly used in German reforestation, as it thrives in heavy soils unlike Larix decidua. So she was off the hook after all.

Sciadopitys verticillata

We don't sell Sciadopitys verticillata any more – the straight species that is. The “Japanese Umbrella pine” (Koyamaki) used to be in high demand for a high price, but today's gardeners have been spoiled into wanting only cultivars. That's ok because one can root or grow from seed the rootstock, then grafts take virtually 100%. The Hillier Manual of Trees and Shrubs says that Sciadopitys “should be planted in every representative collection of conifers,” but then the book lists only one cultivar – 'Sternschnuppe' – from Wittbold-Muller in Germany, before 1984. But Europe is full of interesting cultivars besides 'Sternschnuppe' (shooting star), and I have been to W-M's nursery and they have introduced many other very nice cultivars. The nursery was a well-tended showplace 18 years ago upon my first visit but has fallen on hard times since. It was sad a few years ago to see row after row of umbrella pine ruined because they were growing into each other, and apparently there wasn't a market for them anymore.

Sciadopitys verticillata in Forest Grove, Oregon

I've never seen Sciadopitys in the wild*, but the tallest tree I know is growing in front of a beater house in nearby Forest Grove, Oregon – just 5 blocks away from where I grew up as a kid. I would estimate it to be over 100 years old, but how it got to Forest Grove in the first place I don't know. According to Hillier the species was “first introduced [to Europe] as a single plant by Thomas Lobb in 1853, later more successfully by both Robert Fortune and J.G. Veitch in 1861.”

*The Baltic region is on the other side of the world from Japan, but it is home to the largest known deposit of amber, known as Baltic amber. Infrared microspectroscopy of the amber suggests that conifers of the family Sciadopityaceae were responsible, and the process dates from about 44 million years ago.

Thuja standishii

Thuja standishii (nezuko in Japanese) is an evergreen conifer native to southern Japan. As a timber tree it is grown in plantations for its waterproof, and pleasantly-scented wood. Along with Chamaecyparis obtusa (hinoki), Sciadopitys (koyamaki), Chamaecyparis pisifera (sawara) and Thujopsis dolabrata (asunaro), they and Thuja standishii comprise the “Five Sacred Trees of Kiso.” Temples were built from these five trees, but the great Kiso Forest was off limits to the common people, and if they were caught poaching they were punished with death. In spite of such drama the botanic name is rather boring: the genus name is the Greek name for a kind of juniper and the specific name honors English nurseryman John Standish (1809-1875). Besides the Thuja we have a Lonicera standishii and a golden Taxus baccata 'Standishii' and Standish and Noble at Sunningdale produced Rhododendron hybrids.

Thujopsis dolabrata

Thujopsis looks kind of like a Thuja on steroids, in that the former displays larger leaves on flatter branchlets, in fact it has been commonly called the “Elkhorn cypress.” Thujopsis propagates easily by rooted cuttings but I suppose it would be compatible grafted onto the various species of Thuja. Thujopsis is a monotypic genus and the opsis part of the name means “resembling,” resembling Thuja. The specific epithet dolabrata means “hatchet-like,” referring to the shape of the stomata.* Thujopsis is commonly found in arboreta – hardy to USDA zone 5 – but is not so common in home landscapes. I used to grow 'Variegata' but sales were weak because of its ungainly growth habit and because the portions of cream-white foliage were not very stable. 'Nana' is a better cultivar with its dwarf, compact spreading form, and where all parts are smaller than the type. I don't understand why Thujopsis is not more common in landscapes – it is certainly attractive and easy to grow – but then I am not on a mission to convert anyone just because I like a certain conifer. The beautiful specimen photographed above thrives in Portland, Oregon's Hoyt Arboretum amongst the weeds where it receives no care or supplemental irrigation. I suppose that less than one out of a thousand visitors to the arboretum have ever noticed it...which is a shame.

*In botany, a stoma (plural stomata) is the Greek word for “mouth,” and it refers to a pore that facilitates gas exchange, usually found on the underside of the plant leaves.

Taxus cuspidata 'Rezek's Gold'

The typical nurseryman – like me – detects no difference between Taxus baccata, the “Common” or “English yew,” and Taxus cuspidata, the “Japanese yew.” There are plenty of cultivars for each species, but since T. cuspidata comes from northeast Asia it is more winter hardy than T. baccata. In cold areas one could also try growing Taxus x media – the hybrid between the two species – that has the unceremonious common name of “Anglojap.” If you encounter the specific name of T. caespitosa, just know that it is a synonym of T. cuspidata. I find T.c. 'Rezek's Gold' to be an attractive cultivar, although it must be perfectly sited in Oregon. If in full PM sun it will burn in summer, but if grown in too much shade it will appear greenish. The selection, from the late Ed Rezek of New York, has been variously labelled Taxus 'Rezek's Gold', Taxus baccata 'Rezek's Gold', Taxus caespitosa 'Rezek's Gold' and Taxus cuspidata 'Rezek's Gold', but since the late Edward Rezek sent it to me with the latter name, about 15 years ago, that is the name that I use. For what it's worth, the Royal Horticultural Society's Encyclopedia of Conifers differs and lists 'Rezek's Gold' as a species of T. baccata. Obviously I wonder who, who has decided that, who has concluded that? It is not an unimportant question...since I don't want to purvey plants that are not sufficiently winter-hardy to survive in cold areas.

Today's blog has purposely championed a lot of little-known or under-appreciated conifers from Japan. One reason is so that I can research and learn a little more about them too. It is one thing to grow, and even to sell, a Japanese species, but quite another to really know the intimacies of the species, to know the real creature. The nurseryman has the upper hand over the botanist and the taxonomist, those who deal with dead, pressed herbarium specimens. The nurseryman, on the other hand, feels, smells and has to scrub the pitch off his hands when he works with the plants, so we know them very differently than the botanist. And then, of course, the botanist's livelihood doesn't depend on the plant or a crop to survive and thrive under his care, whereas the nurseryman still has children to feed.

I would much rather that my precious daughter marry a hard-working, dirty nurseryman over a clean finger-nailed botanist, but maybe that's because I am a dirty nurseryman and not smart enough to be a botanist.

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