Copyright 2002-2006. Laurence C. Hatch. All Rights Reserved.
All downloading, printing, saving to media, imaging, screen capture, or offline use is prohibited.
Duplication by any means, method, or technology is unlawful.
Do not link to this page.

Acer griseum at the Biltmore Estate in Asheville NC. Summer 2003. This is not a well known example among the world's fine collections but is one of the more colorful, even voluptuous clones I know. Some of the new ones are too flaky or dismally dark for my tastes. In the international scope of Paperbark variations it fits what I call the Golden-Tan Subgroup. One needs a balance between smooth, pigmented sections and the exfoliating sections. This tree gets it right and having a split trunk gives it an extra measure of interest. In the left photo you will note the roof of North America's largest and most grand mansion in the background.

Longwood Gardens. June 2005. This example is glossy orange and "typical" in bark.

Winterthur Gardens. June 2005. This old example is on the winding road to the Visitor's Center and not in the main or formal gardens - thus many people may not see it unless they slam on their brakes and stop the traffic flow. The stop was well worth it as I slammed my new Billy Lane sunglasses to the seat and rudely grabbed my camera. Branching is wider and more complete than many examples of this age. It is not typical and is in the less glossy group (bark not very shiny) with bark more red than yellow or orange, having a matte finish. It is only slightly erect. The shiny sorts are popular for they look like flaky lacquered furniture but these "duller" examples (not unlike many Lagerstroemia faurei) are equally charming on their own merits.

click image
Durand-Eastman Park (DEP), Rochester NY. August 2005. This is clearly the best AND largest paperbark maple on the planet. It is one of three trees visible from the road at DEP in a group. There are about 20 more trees in the woods, some thick, most thin and wild-appearing.

click image
This is the group photo with the large tree above on the extreme right. These are larger because they probably got more sun and did not suffer under the canopy of 80 foot tall conifers. Kudos the the Monroe County Park Department for cleaning, clearing, and preserving this arboretum so it was in better shape than I remember it from regular study trips from 1978 to 1982. Bernard Slavin would be proud but I think he would have added a couple hundred more taxa, even if they came from his own pocket or seed flats. LCH.

click image
This tree is from Durand-Eastman but not one of the three giants above. It is a tree on the slope facing what I call the "Pinetum Valley". This tree is very fruitful compared to the others and seems to get a bit more sun on the canopy than others.

click images
Durand-Eastman Park, Rochester, NY. August 2005. Here is a sampling of perhaps 20 paperbarks still deep in the woods of the hills heading down to Pinetum Valley. The example on the extreme right approaches the Golden Group while most in this woods are typicaly dark and orange.

click image
Another DEP tree in Pinetum Valley but one given some sun. The position of this tree is so remarkable as it reaches to nearly 50 feet tall and has half a dozen 80 foot tall Chamaecyparis pisifera 'Squarrosa'  towering over it like fluffy blue redwoods. Those tufty, mossy, blue giants are probably the best of that cultivar group on the entire planet as a group. One needs a full century to get an arboretum scene this good. Not the richest man on earth can buy a scene like this. And that is real rarity and the true nature of treasure. LCH.

Morris Arboretum. June 2005. This mature beauty is fairly typical with glossy orange bark and somewhat upright form. It hardly looks planted in the green sod and almost appears like a leafy bronze statue erected there. That aspect reminds me of W.J. Bean's quotation of Charles Eley in Twentieth Century Gardening where he described the species as "rigid as a column of steel". There is often a stiff, austere, metallic quality to the Paperbark Maple and in some gardens young plants have an awkward, wallflower, installed appearance until they "grow in" for at least two or three decades. In some poor soils and sunny stressful positions they grow very slowly and are quite unimpressive.

Gardens tend to have Paperbarks just to have and mention them but it may years before the things are truly beautiful. I've seen unhappy plants hover around 8-12 feet as rusty sticks for nearly two decades. Hard clay southern soils are no friend of this maple. Some people are disappointed at what nurseries can be expected to furnish as specimen trees and what those trees will do in the next few years. People see photos as nice as these here and expect that result in a couple of years. This is not your pop and plop Norway Maple that will transform and conquer your garden space in a few years. This species requires reasonable patience yet not the kind needed for majestic live oaks. Expect 30 years and any satisfaction you get before then is a real blessing. Acer griseum is more than living art, it is art in progress and there is no refund or guarantee on the enduring patronage! She can be a tad grizzley, lean, and inelegant for years; not unlike a gangly teen with Supermodel in her genes.

Shiny, bronze poles with far too little foliage and no curvaceousness and thin branching are not uncommon with A.g. That said, I've seen 15 year old trees as sinuous, lustrous, and pretty as could be expected in twice the time. Some species peak after 45 and this is one of them.

Dawes Arboretum. Summer 2003. A second, younger tree with unusually dark red bark for such a young plant. It appears to be 100% Paperbark. The future of Paperbark clones will be younger trees which develop high amounts of exfoliation and color in a shorter period of time.

As a quick aside, I do have a cute story about the species and a group of very informed Japanese visitors to the 9000 taxa-drenched JC Raulston Arboretum. We curators were asked to be ready for them, offer directions, and perhaps resolve their curiosity on unfamiliar American clones of beloved plants like Japanese maple, Liriope, and Nandina which NC State had in worldclass quanitities. That day Dr. Larson had just completed a study of Easter Lily production and offered unlimited flowering pots to the Arboretum staff for the taking. In our demented, disturbed (not so unusual) lunch hour we curators decided to pull a prank on our Asian guests and quickly fabricated an authentic-looking, professional label along that line. With the benefit of wire twist ties we attached about 20 fresh Lilium longiflorum blooms to a young Acer griseum of about 15 feet tall. The job was done very carefully and with wire hidden among the foliage. The waxy pure blooms were of the finest, highest floricultural perfection. The engraved black label read Acer liliflorum. The huge white trumpets flying with golden pollen stuck out from all angles from the branches with the pedicels angled at surprisingly realistic angles and even distribution. Our guests arrived and cameras snapped amid various comments. We stayed quiet and noticed some contorted faces. We tried to hide our smiles. Heads turned and looked very close. One man tugged at a flower. The label was noticed and the peeling bark scrutinized for the what it surely had to be. More snaps. The tension was interrupted as one photographer remarked in rough accent "very good trick". Then there was scattered laughter and nods, approvals all around. More clicks.The weary group had no doubt endured endless hours of precast, pedantic garden tours, most displays familiar and predictable. Here was a garden and staff with humor and they appreciated the cinnamon-barked Acer liliflorum even if a fabrication and insane botanical fantasy. LCH.

Tyler Arboretum. June 2005. A very erect example. Bark is glossy and orange at the base. The main difference between this and many other specimens is that the upper branches are very dark, blackish-brown.The photo on the left shows the unusually dark upper limbs in good detail. The tree to the right is Acer cissifolium. I think a good breeder could do something with these black-branched examples, perhaps making a good clone on the order of Hydrangea macrophylla 'Nigra' that looks stunning in winter against a pale wall. We have the pale Golden-Tan Subgroup on one side, the regular oranges and orange-grey hybrids in the middle, and this Black Subgroup on the other extreme. 

click images

Highland Park Arboretum. August 2005. This group of plants is not near the big Rochester Group examples (shown below) across from "The Castle". These are near a residential street and adjacent to the Douglas Memorial. I have put one of the trees with the Rochester Group hybrids since it has lots of gray in the bark. Most of these others are all golden-amber or dark orange. At least one of these trees seems to be in the Golden Group or very close.

click images

Horticultural Test Gardens, Cornell Plantations, Ithaca, NY. August 2005. This group of three trees includes two dark and one paler example (tending towards but not clearly of the Golden Group).

Click the NOS logo for
complete society information.

Y.H. Joung, M.S. Roh, and S.E. Bentz. 2001. Characterization of Acer griseum and its putative interspecific hybrids. Acta Hort. 546: 217-220 in Proc. Int. Symp. on Molecular Markers (2001). (This very important paper did RAPD marker analysis on a few existing species accessions and 9 newly created interspecific seedlings bred at Glenn Dale. SAS clustering analysis showed that the pure A. g. from USNA differed very much from A.g. at Arnold, Morris, and one Gotelli Collection tree. Further work to determine if A.g. has genetic variation comparable to A. negundo DNA variation over the geography is suggested.

The newly created hybrids of A. nikoense and A. griseum showed intermediate morphology in terms of leaf area, leaf length, and leaf width. Petiole length was close among all the parents and hybrids.

The new hybrid seedlings clustered much closer to A. nikoense as well has having leaf dimensions much like the larger-leaved species. Heterosis or hybrid vigor does tend to shift things toward the more vigorous parent with grander morphological dimensions when the parents diverge so much.  The hybrid seedlings had pinkish-red fall color said to resemble A. nikoense but later as would show influence of A.griseum. Acer triflorum clustered closer to A. nikoense and the hybrids.

This article brings up one very strong question. Can any accession anywhere be suggested as a hybrid of A. triflorum x A. griseum? I have yet to find one that would fit general intermediacy of both bark AND foliar morphology or was designated by the originator as an attempt of this cross. There are some examples that compute in my mind to have bark traits blended from both those species but nothing suggests an even merger of leaf characteristics.

click image
Tyler Arboretum. June 2005. Another lovely example in the Golden Group with more light shades than strong, dark orange-brown ones. This is a second example that is much less erect than the tree above. Here the bark is conspicuously more yellow, upper limbs not so dark, and bark exfoliations larger and smoother. I consider both of them attractive, worth cloning for study and further evaluation.

click image
This one Highland Park tree is surely of the Golden Group and does not appear to be a interspecific hybrid.
 

See above photos for other Golden Group examples.

click images
Acer nikoense. US National Arboretum. June 2005. Let's look at the pure A. nikoense for comparison. Note the lack of orange and exfoliation qualities in the bark. Also note the lack of lobing in the leaves and well as their larger size then most A.g. LCH.

click images


Highland Park Arboretum. August 2005. I went to the oldest Nikko Maple I knew to get us some clear traits. Here is one boring, plated, gray bark and it could not be mistaken for A. griseum or any of the Rochester Group hybrids. Yea, there is a faint hint of amber in the fissues but nothing like the proposed hybrids shown below where orange/amber is easily 40-60% of the surface.

Since this tree (probably dating from 1912-1920 as are surrounding specimens) is also a Rochester maple in the same garden where the hybrids originated, the comparisons are particularly valid. Note the large foliage with no regularly lobing or teeth. There is a tooth or two but nothing so regular as 3-7 per side as A. griseum and most Rochester Group hybrids.

Acer nikoense differs from A. griseum mainly in:

• 1) Bark all grey to black shades, lichens aside - no major orange, yellow, or amber sections or exfoliations. The very old Nikko maple at Highland Park Rochester has tiny hints of amber among the fissures on close inspection (< 2% of surface) but appears all grey and black from 10 feet views. The famous Rochester Group hybrids radiate orange and amber shades from 20 feet or more, these coveing 15-45% of most limbs.
   
• 2) Bark has fissures and clefts instead, some small plates - no large plates, exfoliating sections, or smooth zones
   
• 3) Leaves with slightly deeper, more sunken veins with less flat blades than most A. griseum. The hybrids can have somewhat sunken veins.
   
• 4) Leaflets are up to 5-7 inches long and 2-3 in. wide - A. griseum rarely have leaflets over 4 inches long and 1.5 inches wide.
   
• 5) Leaves untoothed or barely undulate while A. g. tends to have 3-5 pairs of defined teeth or small lobes
   
• 6) Leaves early to color in autumn and not lasting so long as A.g.
   
• 7) Leaves mostly yellow in fall, sometimes reddish - A.g. is almost always in red to orange shades. There is probably a genetic connection between autumn foliage and bark pigmentation.
   
• 8) More cold hardy - USDA 4 is doable - pure, non-hybrid A.g. rarely thrive above USDA 5. One should remember that Rochester NY (Highland and Durand-Eastman Arboreta), a source of many plants and hybrids, is near a massive warming lake (Ontario) and while officiallly USDA 5, it approaches zone 6 in some spots.
   
• 9) Habit may be shrubby or a multi-trunked tree - A.g. is usually single trunked
   
• 10) Samaras nearly parallel to 60 degree divergence - A.g. diverges more at 60-90 deg.

click images

Highland Park Arboretum (HPA), Rochester NY.
August 2005.
One of two very clearly hybrid trees. These are very attractive trees but I cannot say the same for younger examples of this parentage. LCH.

Highland Park Arboretum (HPA), Rochester NY.
August 2005.
This is one of the two trees covered above but I wanted to single out this photo for one reason. Note the uneven distribution of the exfoliation and colors in terms of orangeness. Some sections of the trunk are much more gray and intact like A. nikoense and other portions almost "break out" to the underlying pigments of the paperbark genes. Most of you (even top maple experts) have never seen these old Rochester trees and I hope these photos shine some light on the hybrid phenotype.

click images

Scott Arboretum, Swarthmore College, PA USA.  June 2005. A much younger tree than the HPA but intermediate in bark colors and leaf morphology. If you look at the Rochester trees, this young example is likely to "break out" with more orange as the bark expands and cracks.

Dawes Arboretum. Summer 2003. This tree has no connection to Rochester as far as I know (inquires continue) but clearly has the frosty, grayish bark flakes of an A. nikoense hybrid. The foliar morphology here is clearly close to A. griseum so it could be a segregate or introgressant back to A. griseum.

Highland Park Arboretum. August 2005. Another group of Paperbarks (Rochesters has dozens of them) quite far from the first examples shown above (near the Douglas Memorial). This one has enough dark grey on the bark to make me think it has a least a third of some other species. The foliage here is much closer to A. griseum. This too could be a source of  'Girard'.  This is a plea for DNA analysis. Since the leaves are small and the bark is coarsely flaked, could this have some A. triflorum in the mix?