Friday, June 17, 2016

The Terrific Tridents

Acer buergerianum

Acer buergerianum is commonly known as the “Trident maple” due to its (usually) three-lobed leaves. I met its acquaintance rather late in life at the beginning of my nursery ownership, and I suppose it was when I was about 30 years old. I've known of Acer palmatum since my childhood because my family had a red laceleaf maple in the back yard, and we were warned not to kick the ball into it because it was “valuable.” Later, since I intended to begin a plant nursery that would specialize in Japanese maples – the red laceleafs and red palmatum uprights such as A.p. 'Bloodgood' – I assumed that the Acer genus began and ended with the palmatums.

Acer pycnanthum

I scheduled a pilgrimage to the maple guru of the time – J.D. Vertrees (1915-1993) shortly after his sensational book Japanese Maples was published – to visit his Maplewood Nursery, because his book revealed that there was far more to being a “Japanese maple” than just the red palmatums. Heck, there were even green selections, and variegated ones, and dwarves and...and...then he brought up the concept of species of Japanese maples. He championed Acer pycnanthum and wondered if I liked it; I did not – it reminded me of Acer rubrum, thousand of which were overused on Portland streets. Then Vertrees herded me past an Acer buergerianum 'Miyasama yatsubusa'. I didn't recognize it as a maple of course, due to its ivy-like leaves, but he pointed out the tiny green samaras. By the time I was through with my visit I had already forgotten the cumbersome specific name of buergerianum, as I was saturated with my encounter with myriads of palmatum cultivars.

Acer buergerianum 'Naruto'

I'm foggy about my first acquisition of any Acer buergerianum, and even though I kept meticulous notes at the time, the source was bungled on the computer by an insecure employee with borderline personality disorder who kept the glitch secret and then I discovered six months later that all plant sources were fouled up. Ah, those were the days when more harm than good came from computer operators who described themselves as “competent” – or even “good” – when I interviewed them for the job. Anyway, I put back my sources for my master plant list as best I could from memory. Possibly A.b. 'Naruto' was my first cultivar, and I think it came from one of the plant-collecting doctors* who I befriended early on.

*Dr. Bump, Dr. Corbin and Dr. Mossman – sadly now deceased – were important early plant sources in my career.

Friedrich Miquel
The buergerianum species was named by Friedrich Anton Wilhelm Miquel (1811-1871), a Dutch – but German born – botanist who toiled in Utrecht, The Netherlands, and I have been to the botanic garden there. Miguel sported fantastic gray sideburns that draped down to his collar, and it's a shame that he only lived to age 59. The specific epithet honors Heinrich Burger – with an umlaut over the “u” – a German physicist, biologist and botanist who was employed by the Dutch government to study the Japanese flora and fauna. It was common at the time for German-born scientists to labor for the Dutch, and perhaps most notable was Philipp von Siebold who oversaw Burger's activities. The Japanese didn't trust the Europeans on their mainland, but they did allow research on the small island of Dejima, located in the Nagasaki harbor. So Burger discovered Acer buergerianum, but he never officially described his findings, rather deferring to the botanical cognoscenti back in Europe. Burger was also honored for Azalea burgeri which is now lumped under Rhododendron indicum, the fern Lepidomicrosorium buergerianum and the pipewort Eriocaulon buergerianum whose scientific name is derived from Greek erion meaning “wool” and caulos meaning “stalk.”

Acer buergerianum ssp. ningpoense

Acer buergerianum at Kew
Acer buergerianum was once known as Acer trifidum Hooker and is native to mountain forests of Japan and eastern China where it forms medium-sized trees with broad canopies. The species was introduced to the Royal Botanic Garden, Kew, in 1896, and that collection is a fantastic place to see enormous specimens of many other Japanese maples. I have seen grand trees of A. buergerianum in Japan as well, and often I identify them at first by their shaggy gray-brown trunks before I see the leaves. Subspecies ningpoense is from Ningpo in Zhejiang province, China, and it is a small tree or shrub with a dark brown trunk more smooth than the type (but still exfoliating). It should be grown in full sun and is probably only hardy to USDA zone 7, or zero degrees F. Its reddish new growth contrasts nicely with the older dark green leaves, and fall colors can range from brilliant yellows, oranges to reds.

Acer buergerianum 'Miyasama yatsubusa'

Acer buergerianum 'Miyasama yatsubusa'

Acer buergerianum 'Miyasama yatsubusa'

Yuki Tamori with Acer buergerianum 'Miyasama yatsubusa'
Cultivars of A. buergerianum are not plentiful in the trade, and I know from my own experience that selections such as 'Miyasama yatsubusa' are so slow that you probably never turn a profit. Nevertheless I have a large specimen in the original Display Garden which stands 13' tall by 7' wide; I have never seen one larger, but surely in Japan there must be an old tree twice my size. Another reason for the paucity of A. buergerianum cultivars is that the graft takes can be poor. I don't say that it has to be poor, or that it ever was poor for you, but for me and other I know, A. palmatum propagation is relatively easy, but not so with A. buergerianum. In fact we can achieve a better percent via rooted cuttings under mist than we do grafting, but then you'll have an even more-dwarf tree.

Acer buergerianum 'Mino yatsubusa'

A.b. 'Mino yatsubusa' surprises maple novices that it is a maple at all, let alone a Japanese maple. It demonstrates how polymorphic the A. buergerianum's leaves can be, ranging from 'Mino yatsubusa's' willowy long middle lobes to 'Kifu nishiki' with heart-shaped leaves with a single lobe, not trident at all. 'Mino's' leaves are glossy green – and thus difficult for me to photograph – but in autumn they turn rich in coloration with green, yellow, red and purple, sometimes at the same time. Again, note how I write “difficult for me” because for you it might not be, just as when I admit that something is difficult for me to propagate – where I say it can be difficult or for me it is difficult. The point is to be careful about stating absolutes because nothing is ever absolute – whoops, I just did it myself! In 1978 Vertrees in Japanese Maples describes 'Mino yatsubusa' as “very difficult to propagate,” just as he does for other tridents like 'Wako nishiki' and 'Nusatori nishiki'. The Vertrees/Gregory 4th edition rehashes much of what Vertrees said in the first edition, and I find much to be inconsistent with my experience. For example Vertrees describes Acer palmatum 'Goshiki kotohime' as “quite difficult to propagate” in 1978 and then we read it verbatim in the 2009 4th edition. Grafts are not “difficult” at Buchholz Nursery because we keep our stock in greenhouses to encourage long-internodal growth, and our graft percentage reaches about 75-80%. We also root 'Goshiki kotohime' and over the past twenty years our percent averages at least 90%. The same is true with A.b. 'Mino yatsubusa', where it strikes root quite readily from soft wood cuttings under mist. Try and graft or root it from an old specimen out in the landscape and I can believe in the “difficulty.” What I have learned in my long tiresome career is that I actually know less than when I started, and also to accept the fact that another grower might be superior to me with a certain plant.

Acer buergerianum 'Wako nishiki' in May

Acer buergerianum 'Wako nishiki' in July

Acer buergerianum 'Wako nishiki' in October

Acer buergerianum 'Wako nishiki' is a fun maple to grow with its white new foliage in early spring...which evolves to more green-white by late spring, and hopefully just in time before the 100 degree days arrive. Vertrees/Gregory describe it as a “very slow-growing compact shrub” that is “not easy to propagate and requires extra care in cultivation.” Not to overly harp on Vertrees, but that description comes from his limited experience. I dug a 16' tree out of the Display Garden that was only 12 years old – hardly a slow-growing compact shrub. We don't give our younger plants any “extra care,” as I am against anything that's high maintenance, and if discontinuing it is the best option, then so be it. That's actually a very Japanese concept: that if a nail sticks up – i.e. individuality – it will be pounded down. We know that the Japanese word nishiki usually means “variegated,” but wako is more difficult to understand. It can mean that the maple comes from Wako city which is located near Saitama – an old historical horticultural region located outside of Tokyo. But that name itself can be derived from the Buddhist inclination to “soften your light,” to not present yourself as the full unadulterated you. That would be too much and it is not considered good form. This explanation of wako is the supposition of my wife after seeing the characters of wako in Yano's maple book. I have come to accept that no question to her will come with a quick and simple answer, just as understanding her and her culture is never simple. It seems like you have to not try too much because your effort and desire to know is a hurdle that gets in your own way.

Acer buergerianum 'Hana chiru sato'

Somewhat like 'Wako nishiki' described above is Acer buergerianum 'Hana chiru sato', but it is perhaps more of a wimp as my one and only tree succumbed. New spring growth is cream-white with a pinkish hue, then it becomes more white with green veins. Later in summer my tree petered out so I can't describe it beyond that, but at least I could take a nice photo...and thanks for the memories.

Acer buergerianum 'Angyo Weeping'

Acer buergerianum 'Angyo Weeping'

Acer buergerianum 'Angyo Weeping' is saddled with an invalid name as one cannot combine two languages for a cultivar name according to the rules of international nomenclature. 'Angyo shidare' would have worked however. As the name implies it displays a strong pendulous form and the original tree can be found in Angyo which is located near Tokyo at the Kobayashi maple nursery. This area was chosen for nurseries due to the excellent underground water and red soil (Kanto loam) that the nurserymen incorporate into their potting media. There used to be an Angyo Maple Nursery which in the 1930's listed over 200 cultivars of Japanese maples, but I don't know if it continued after the War. 'Angyo Weeping' can be rooted or grafted low, then trained to the desired height and it will then form an umbrella shape. The same can be achieved by grafting onto a standard, but it might not look as attractive in winter. Summer foliage is glossy green and it tolerates heat well as long as it receives adequate moisture. Fall colors range from orange to red to purple.

Acer buergerianum 'Hime toyo nishiki'

Acer buergerianum 'Toyo Tricolor'

Acer buergerianum 'Hime toyo nishiki' was selected for being dwarf and for leaves with pink and white on green variegation. Often the middle lobe is sickle-shaped, and frankly I don't find the cultivar to be very attractive. It originated as a seedling from A.b. 'Toyo Tricolor' – yes another invalid name, and I wonder if it's ok to just call it 'Toyo'. Whether it's ok or not, 'Toyo' is far more vigorous and healthy-looking. Of course that can be a problem at Buchholz Nursery where many of the variegated maples are treated so lavishly that they burst out green new growth without the colors.

Acer buergerianum 'Street Wise'

A few years ago I bought a few starts of Acer buergerianum 'Street Wise' from another wholesale grower, and even though it was patented – which I don't like – I decided to find out why it was a wise choice for street planting. I never could conclude why, as it seemed no different from the type, except that a specific clone usually displays more uniformity than random seedlings. So basically someone noticed a trident that looked particularly nice, and through Tree Introductions Inc. of Georgia, patented and named 'Street Wise', and through marketing someone gets to collect a royalty. Big deal. I do like Tree Introductions Inc.'s motto of “Greening the Third Millennium,” except that implies that there were no horticultural activities B.C. which is not correct. Anyway, I've read that 'Street Wise' can grow 30 to 45' tall by 25 to 40' wide, and I don't find those dimensions to be advantageous for street planting. I invite anyone to convince me that this is a great tree for urban planting, otherwise I'll conclude that we just have some Georgia hucksters bent on making a dollar.

Acer buergerianum 'Tancho'

Acer buergerianum 'Naruto'

Acer buergerianum 'Naruto'

I used to grow Acer buergerianum 'Tancho' and 'Naruto' and I found them to be pretty much the same – vigorous green uprights with glossy curled green leaves that turned orange and red in the fall. I knowingly sold my last of each – kicked them off the ark – because sales were always slow even though I found them to be kind of interesting. Neither of them reverted as does the similarly curled leaves of Acer palmatum 'Okushimo', which is another maple I discontinued. My cavalier approach to horticulture, where thumbs are up one day and down the next, occasionally leaves me wistful and bittersweet, just as when I look back at the parting with an old girlfriend, or rather a young girlfriend from long ago.

Acer buergerianum 'Inazuma nishiki'

I'd like to describe another trident, 'Inazuma nishiki', but I don't grow it. I've seen it only one time and that was in Masayoshi Yano's collection. It is not included in his Book for Maples either, but my photo is proof that it exists. It makes me think of all of the thousands of people I have encountered, but just in passing. Happy children, pretty girls, old men, gangster boys etc. – I think every passing image remains somewhere in my brain, crammed in with my thousands of plant encounters. Maybe I'll meet 'Inazuma nishiki' again, maybe not.

Acer buergerianum 'Michael Steinhardt'
Leaf underside

Acer buergerianum 'Michael Steinhardt'

I was very impressed with a Don Shadow (of Tennessee) introduction that he named 'Michael Steinhardt', even though I cringe when plants are named after people. As you can see it shouts with golden foliage – my photo was taken in May – and Don claims that it does not burn. Best of all it is not patented and he gave me a start, and now we are propagating it also. As usual for us we keep the first tree indoors to encourage longer propagating shoots than if we were to plant it straight away into the garden. As with many golden plants I can see that it colors more green when inside, and no visitor has ever passed it with any notice. Shadow named the tree for a New York investment banker who has a private arboretum/zoo in Mt. Kisco, New York, as he has patronized Don's nursery. Mr. Steinhardt has visited me twice in Oregon and his garden contains some of my plants; this fall I hope to visit him on his home turf, to see what he has done with them.

Acer buergerianum at the Pacific Rim Bonsai Collection

Pinus thunbergii

Rhododendron indicum 'Kinu no hikari'

Many maple references mention the popularity of A. buergerianum as a subject for bonsai culture. My late grandmother despised bonsai – she likened it to “torturing children” – and with all of the copper wires used I can see her point. Personally I admire the poetry of nature that is created whether the artist uses pines, Rhododendrons or Japanese maples, and I am fortunate to live relatively close to the Pacific Rim Bonsai collection in Federal Way, Washington, adjacent to the fabulous Rhododendron Species Botanic Garden.

I'm sorry for Acer buergerianum, that this wonderful Asian species is scientifically saddled with a German's epithet. As it originated in eastern China, it's Chinese name is san jiao feng, and it is native from Shandong west to southeastern Gansu, south to Guangdong and Taiwan, and southwest to Sichuan – so to quite a large area. It was introduced very early to Japan, where its name translates as “China maple.” I find it interesting that Japan and the Western world have selected cultivars, but I know of none from China. In any event I hope this blog will help you to appreciate the species a little more.

No comments:

Post a Comment