Friday, February 20, 2015

The Origin of Species – Maples That Is

Acer palmatum

Acer palmatum

Acer is the classical Latin name for "maple," although it should be pronounced Ah-ker. That is how I pronounced it the first few years of my career at Buchholz Nursery, but I changed to A-sir because I was getting strange looks. The nursery where I worked previous to here never used the scientific name for maples, and some nurseries still don't to this day. The origin of the word Acer is thought to be the word for "sharp," due to the pointed leaf lobes on some species. Acer is in the Sapindaceae (soapberry) Family, and that in the Order of Sapindales. Thus maples are related to chestnuts and lychee fruits, and also to Blighia sapida – a tree from Guinea that was named for the Bounty captain, William Bligh.

Acer saccharum

Acer saccharinum 'Born's Gracious'

It's somewhat annoying that Acer saccharum and Acer saccharinum have similar names when they are very different types of maple. Annoying, in the sense that my employees must be reminded what rootstock to use when we are propagating. Both specific names are from saccharinus, referring to the sugary sap, but saccharinum is in the Section Rubra, while saccharum is in the Section Acer. The word sugar was derived from Old French sucre, which was originally from Sanskrit sharkara. In India, Alexander the Great's army was greatly impressed with the "honey without the bees." As a term of endearment, sugar was first recorded in 1930, but I have never used it for my wife or children; but I do use the term honey for them. One would think that the word sugar would be spelled shugar or shoogar, right?

Acer cappadocicum

Acer cappadocicum 'Aureum'

Acer cappadocicum ssp. lobelii

Acer cappadocicum ssp. sinicum

A Flora Wonder Blog reader recently sent some scions of Acer cappadocicum 'Aureum'. I have long admired the cultivar because many botanic gardens contain it in Europe, but I've never seen it ever in America. The cappadocicum species can grow to large size, so it is not really a modern-day-garden tree. Its name is from cappadocicus, for it comes from Cappadocia, a region in ancient Turkey, while its common name is "Caucasian maple." Other than my newly acquired A. c. 'Aureum', I have never had the species nor any subspecies on my property. Naturally the botanists have managed to sub-divide cappadocicum, and one such variant is divergens, named because the samaras spread widely. I saw a huge ssp. lobelii at Hemelrijk in Belgium three years ago and was most impressed with its trunk. Subspecies sinicum is from China of course, but when in Yunnan I never saw it. The photo (above) of sinicum is from the Hillier Arboretum in southern England. A mature Acer cappadocicum is a huge monster that would probably take up too much of my property, so I just might sneakily plant one on my neighbor's estate.

Acer nipponicum in June

Acer nipponicum in October

Acer tegmentosum

I'm not sure why I am attracted to Acer nipponicum, but I have a nice-sized tree at Flora Farm. It is splendid in spring and early summer, but when August brings sustained 95-105 degree F days, nipponicum can look haggard. Furthermore, the resigned appearance of summer is never redeemed with bombastic brilliance in autumn, for the faded-green leaves turn to dull yellow, and then to brown. I once asked Peter Gregory, the Acerian author and species expert from England, what rootstock to use to propagate A. nipponicum. His response – somewhat flippant – was to use Acer pseudoplatanus...because it "accepts most everything," but I learned that "most everything" does not include A. nipponicum. The species is from Japan of course, for Nippon is an old name for Japan. The Japanese people bristle at the term Nippon (or Nips) to refer to themselves, and prefer instead Nihon, or Nihonjin for a person from Japan. Acer nipponicum is native to the mountain forests of Japan, but I have never seen it in the wild. Its foliage bears some resemblance to Acer tegmentosum, but the former is in the Section Parviflora, while the latter is in the Section Micrantha. All of my A. nipponicum are seedling-raised then, and they all look the same. Since there is no compatible rootstock for the species, can I also conclude that there will never be any hybrids with nipponicum and other Acer species?

Acer fabri

Acer fabri

Ernst Faber
The non-hardy Acer fabri used to be in my collection, but I no longer grow it. My last specimen reached the top of GH20, so I sold it to a Californian who could plant it out in his zone 9 garden. I occasionally go through reality-checks in my life-career, when I truly wonder: what am I doing? So I got rid of my last A. fabri since it wouldn't survive out in my landscape, but then I soon regretted that I would no longer be with it-her. I miss the chocolaty-red new growth in spring, and when it appears the older evergreen leaves finally drop. I also liked to quiz plantspeople as to what genus it was, and answers would vary from Ficus? – to – Euonymus? Then I would point up into the crown where cute maple seeds were dangling. The species was named for the missionary Ernst Faber (1839-1899) – a man with a most prodigious white beard – who endeavored to "convert the mind of the Chinese to Christianity." I don't know how many souls he was able to convert, possibly none, so I'm thankful for his botanical predilection. Though Faber discovered this maple, it was E.H. Wilson who finally introduced it to England in 1901 under the name wardii.

Acer glabrum ssp. douglasii

Acer glabrum ssp. douglasii

Acer glabrum is a western North American species, ranging from South Dakota to the Rockies to the Pacific, but I only grow subspecies douglasii¸ our Oregon native. I originally became fascinated with it because the Columbia River Gorge has a couple of locations where all three Acer species native to Oregon – glabrum, macrophyllum and circinatum – grow amongst each other, literally touching. But never do they hybridize, to my knowledge anyway. Glabrum is in the Section Glabra, macrophyllum in the Section Lithocarpa and circinatum in the Section Palmata. When I say that I "grow" glabrum, really I don't, as no one would buy it. But I have one tree that I planted next to my eastern woods, where it blends in with the other brush. Glabrum is no one's favorite species, that I understand, but strangely De Beaulieu, in An Illustrated Guide to Maples, states "This tree has ornamental value in North America..." but that in Europe it is "very inconspicuous and lacks ornamental value." On hillsides lush with organic matter and moisture, glabrum will turn straw-yellow in fall. On top of boney mountains with sparse rocky soil, glabrum will color from orange-to-red-to-purple, often at once on the same tree.

Acer sinopurpurascens

Acer sinopurpurasnot "es" – cens is from China, as you would suppose, and the "purple-part" is in reference to the flower color. I've never grown the species, and the photos (above) come from either the Hillier Arboretum or from Kew, but I now can't remember. Apparently, there is a specimen growing at the Arboretum Trompenburg in Rotterdam, Holland, but I don't recall seeing it in that soaked locale, even though I have been there four or five times. I know very little about the species, other than having seen it in England, so I don't know if it would even be hardy for me. It is related to Acer pseudoplatanus – which is plenty hardy – so maybe I actually could grow it in Oregon. Information is so sparse about the species that I'm not sure that anyone even grows a specimen in America. Speak up if you do! An internet search yields such useless information as "An Acer sinopurpurascens in uska species han Magnoliopsida nga ginhulagway ni Cheng [the botanist]. An Acer sinopurpurascens in nahilalakip ha genus nga Acer, ngan familia nga Sapindaceae. Waray hini subspecies nga nakalista." Oh right: the subspecies nga nakalista. Translation please!*

*This language appears to be Cebuano, spoken in the Philippines' Central Visayas region.

Acer sterculiaceum 'Joseph's Coat'

Acer sterculiaceum 'Joseph's Coat'

Acer sterculiaceum 'Joseph's Coat'

Acer sterculiaceum is an interesting species – to me anyway – and one reason is that it was named for the Roman God Sterquilinus, who was the God of fertilizer or manure. Besides the maple, whose flowers are malodorous, Sterculia is a genus named by Linnaeus in the mallow family, and Sterculia foetida is commonly known as the tropical chestnut. A gum is extracted from the Sterculia genus and is used as a laxative and as a denture adhesive, thus double-tasking at the retirement home. Not surprisingly, the African Sterculia rogersii provides a good quality fiber and is best described as a small squat tree. De Beaulieu's book, mentioned above, suggests that Acer sterculiaceum "is a collector's tree with no particular ornamental value." He is mostly right, but I once raised a seedling which displayed delicious variegated leaves, and I felt compelled to name it 'Joseph's Coat'. Alas the variegation wasn't stable, and if the color was too white, it would then burn. But look at the photos above – you too De Beaulieu! – and tell me that it is not ornamental.

Acer rubrum 'Red Sunset'

Acer rubrum

Acer rubrum 'Vanity'

Acer x freemanii

The "good economy" for nurseries was from the 1970's to spring of 2008, and even inefficient companies with mediocre quality could turn a profit. That was also the heyday* for cultivars of Acer rubrum, and they were grown by the many, many thousands by shade-tree nurseries, both large and small. And that's why I stayed away from the species except for the variegated cultivar 'Vanity'. Street specimens of rubrum are beginning to flower now in Portland, where hot air from the local politicians has advanced the season. Acer rubrum is referred to as the "red maple," but I'm not sure if that's for its spring flowers or for autumn foliage, but either would seem to be valid. The species can get huge, and would not be appropriate as a street-tree or for most landscapes, but fortunately there are more compact or columnar selections. Rubrum is similar to the Japanese native, Acer pycnanthum, and I do have the latter at Flora Farm. It's a smaller species with smaller leaves, kind of like comparing Haruko with me. Rubrum also hybridizes with Acer saccharinum and the cross was originally named x freemanii after Oliver Freeman, a plant breeder at the Arnold Arboretum. The photo of freemanii was taken in Belgium in 2011, but I won't be planting one in my landscape due to size constraints.

*Heyday is something in its prime. The Oxford English Dictionary's first citation was from John Skelton's Magnyfycence (1529): "Rutty bully loly rutterkin heyda."

Acer velutinum

Nor will I add Acer velutinum, for its size. This is the "velvet maple," so named for the light brown down on its dark green leaves. The photos above were from the Royal Botanic Gardens, Kew; and when a tree attains this size, it is actually difficult to analyze, unless you could climb to the top of a neighboring tree. Acer velutinum is commonly called the "Persian maple," as its range is from the Caucasus to the mountains of northern Iran. It is probably the second-largest Acer, next to only Acer macrophyllum. I know of a specimen in Seattle's Washington Park Arboretum, so if I really want the species I could visit on a winter day with my secateurs and relieve it of a couple of shoots – nothing would be harmed – and bring them back to graft onto Acer pseudoplatanus, for they are both in the Section Acer.

Dipteronia sinensis

E.H. Wilson
I used to grow Dipteronia sinensis, a plant closely related to the maples, but it perished after I transplanted a large specimen. Just as well since nobody would buy them, but as a shrub or small tree with pinnate leaves, I could usually stump plantspeople with its identity (Rhus? Alianthus?). Dipteronia was first discovered by Augustine Henry in 1888, and was introduced to England by E.H. Wilson working for the Veitch Nursery. The name is from Greek di for double or two, and pteron for a wing or feather, as each seed has two wings. Commonly it is known as the "Chinese Money maple" due to its thin round wafer-like seed. Its range is the center and southwest of China, and while not critically endangered, mature trees are becoming more scarce due to cutting.

I'll retell a story about a discussion with J.D. Vertrees – the Japanese Maple author – at the beginning of my career. By the third visit to his collection he had a feel for what I was about, and he asked if I had any interest in other species of maples, other than palmatum, shirasawanum and japonicum. I replied, "Not particularly." He responded, "Eventually you will." And of course he was right.

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