japanese maples and other choice acer, with adam wheeler of broken arrow
I HAVE A FOLIAGE THING, probably more so than for flowers, so no surprise that a genus of trees I’m particularly passionate about is Acer, or maple, and especially the so-called Japanese maples—which do technically flower, of course, but not in the obvious way a magnolia or dogwood might. I invited Adam Wheeler, Broken Arrow Nursery’s propagation and plant development manager, to my public-radio podcast to talk maples.
Adam and I talked about not just the Japanese types, but also other garden-sized maples for adding interest in every season and garden situation–in pots or the high shade of woodland gardens, to full-sun locations.
my maple q&a with adam wheeler
Q. When I was at Broken Arrow recently, there were many choice things to look at—but I kept noticing the maples you offer, particularly. How many do you grow?
A. In the collection at the nursery, I suspect we have 150 or 200 different maples, and really that’s the tip of the iceberg with this genus.
Q. There are a lot of native American maple species, and Asia has a lot of beauties, too.
A. Our collection spans the full diversity, yes.
Q. So what’s a “Japanese maple”?
A. Loosely “Japanese maple” would be any maple native to Japan, but really what they’re talking about is Acer palmatum, or Acer japonicum, those two species of maples.
Q. There is a third species that gets included in there in listings—the one with the hardest name to pronounce.
A. Yes, Acer shirasawanum also gets lumped in.
Q. And they don’t all look the same. As much as I would say, “I love Japanese maples,” there are some that I don’t love, and some that I really, really do.
A. Among those species, there really is a lot of diversity as far as varieties and cultivars. All those species tend to be small trees on their own, and will get to be about 15-25 feet tall.
But with the diversity of cultivars, you really can find one that will fit just about any garden space: from super dwarf forms on up to weeping forms and very upright forms, as well as just the standard tree forms. We try to carry a diversity of forms and habits to fit different garden applications people are looking for.
There’s also a lot of diversity with the foliage color and texture.
Q. There really is—and that’s what you see at first, if you’re buying a young plant in a container, a smallish plant, like many of us start with, since they can get pricey otherwise. The foliage is what strikes you first.
A. We have standard green-leaf forms, and then some exceptional gold-leaf forms…
Q. …some of my favorites fit in there—you know me with gold leaves!
Q. It’s not lacy or fine-textured as some, but bolder. And on the other extreme of color?
A. We have dark purples as well. The classic purple-leaf form is Acer palmatum ‘Bloodgood,’ a wonderful, durable, 20-foot tall tree with wine-purple foliage that really stands out.
Q. In the North it was almost synonymous with “Japanese maple.” If you went to a garden center and asked for one, ‘Bloodgood’ is what you were directed to. It was hardy, and even near where I garden, you see old trees that have endured many winters.
A. It’s kind of the benchmark for hardiness for Japanese maples, a solid Zone 5 plant (though not a cold Zone 5 plant)—which is kind of the upper end of hardiness for this group.
Q. And I have one or two varieties whose leaves I wouldn’t call purple, but reddish, perhaps—more the warm side of red than wine-colored?
A. Cultivars with that kind of coloration are on a spectrum, and their color also changes through the season. So a lot have the richest color saturation in the spring and it evolves as the season progresses.
Q. Backtracking to hardiness again: The first time I adopted a “Japanese maple,” I wanted something hardy to grow in the ground, but not something with that purple leaf, like ‘Bloodgood.’ A nursery near me, Windy Hill, suggested a Korean species.
A. The Korean maple, Acer pseudosieboldianum, is a wonderful option, especially for folks that can’t grow Acer palmatum, because it’s a full zone more cold-tolerant. It will stretch into Zone 4 conditions. It gets fantastic scarlet and orange fall color [photo above].
Q. And in spring, when it leafs out, it’s such a fresh light green. Beautiful.
A. It’s a wonderful plant, and underutilized.
A. I have a couple of personal favorites. One is ‘Mikawa Yatsubusa’ [photo above right] a very dwarf plant with leaves that are a nice, fresh green and very close to one another. The plants only grow about 2 inches a year, and ultimately get a very sculpted, airy, open framework. In a large container, they look wonderful, and top out at about 5 or 6 feet tall. It reminds me of shingles on a roof, the way the leaves stack up on the stem.
I’m also a big fan of one called ‘Shaina’ [photo above left], a purple-leaf selection with an oval framework, and holds its color saturation through the season. It only gets to be about 4 or 5 feet tall ultimately.
Q. These would be able to be in pots for a good long time.
A. When you grow them in containers, it slows down the growth rate just a little bit, so they often stay more compact for a longer period of time.
Q. I would definitely second that idea, because as you know, I have tortured some of the larger ones—like the full-moon maple—in very large pots for maybe eight or nine years. And I say “torture,” semi-kiddingly, but it’s maybe one-third the height it would be in the ground, because I’m restricting the roots. You do need to repot and root-prune, yes?
A. Root-pruning will help the plant stay happier for a longer time in a pot. Typically, when I do it at home, I do it first thing in the spring, before new growth develops. I pop them out of the containers, inspect the roots, and prune off any girdling or spiraling roots that have developed, and kind of rough up the rest a bit. That’s when I’ll make the decision to put it back into the same container, or into a slightly larger one.
Q. The problem with doing what I did—putting the bigger-growing varieties in pots [which I store in my unheated barn, dormant, all winter]—is that now I’ve moved them up a number of times and reached the largest pot possible. So maybe I need to hand them down to someone a Zone south of me to adopt, who can put them in the ground. [Laughter.]
So what are the basic needs of Japanese maples—how do they grow in nature?
A. They’re actually very tolerant plants. They prefer a slightly acidic soil, but they’re adaptable to varied conditions once established. You want to try to avoid a lot of drought stress, because the foliage can get leaf scorch—dried out. You’re after an evenly moist situation, but not water-logged.
They grow great in full sun or pretty deep shade, but the only thing about shade that I caution people about: You lose some of the fall-color excitement. You won’t get the prominent reds and scarlets, but more yellows in shade.
Q. We didn’t talk much about leaf texture—but are the most delicate, lacey ones actually delicate, or as tough as the others, despite their appearance?
A. The lace-leaf ones can be as durable or more durable than the standard forms. They’re wonderful garden plants. One of my favorites is called ‘Koto No Ito,’ a green-leaf form with heavily dissected, finely lobed leaves that are a rich green color. It’s a wonderful contrast plant in a mixed border, or as a standalone specimen. It gets maybe 12-15 feet tall ultimately, and I love it in containers as well.
Q. Is it Zone 6, too?
A. It’s probably a Zone 5 plant; I’m in a warm Zone 5B, and it does well for me.
Q. What about variegated forms of Japanese maple?
A. There are lots of them—ones with pure white variegation, or those that integrate yellow or pink into the mix.
Q. Are there other smallish maples you want to recommend, beyond the “Japanese maples”?
A. One of my favorite groups that I think is underutilized are the snake-bark maples, which includes six or seven different species. They get the name from their bark characteristic, which has prominent white striping in it—an outstanding feature on its own.
Q. Which species fit in here?
A. One is Acer pensylvanicum [photo left], our North American native moosewood. There are some Asian species, such as Acer tegmentosum, from Korea and Manchuria—it’s common name is the Manchu striped maple. Acer rufinerve, the red-vein maple, is a Japanese species. And then there is a hybrid group called Acer x conspicuum, which is kind a group with mixed parentage, including those I mentioned.
Most of these are 15-to-20-foot trees, or you often see them as large, multi-stemmed shrubs–low-branched trees. They like a little bit of shade, like in the second level under large, overstory trees—so in a woodland garden as a winter-interest element with the prominent striped bark.
In some the stems turn scarlet in the wintertime—beautiful in the snow, or against the right backdrop. There’s a hybrid snake-bark maple called ‘Phoenix’ that has incredible scarlet stem coloration in the wintertime, so you have white- and scarlet-striped stems. [Photo above: a range of features in all seasons from snake-bark maples.]
Q. Other favorite garden-sized kinds to recommend?
A. The trifoliate maples are another great group. Acer griseum, the paperbark maple [photo left] is probably the best-known, with an outstanding amber exfoliating bark, and really nice autumn color. And being a New Englander, I wouldn’t garden without sugar maple, Acer saccharum—the hallmark of the autumn in the Northeast.
Q. Give it a little more room than these other guys.
A. Yes, it’s a big tree—but there is a dwarf, called ‘Millane’s Dwarf,’ that only gets to be about 15 feet tall.
more from broken arrow
- All the maples on Broken Arrow’s mail-order site are here (even more at the nursery)
- Get details on visiting Broken Arrow in Hamden, Connecticut.
- Call Broken Arrow at (203) 288-1026 or email to info [at] brokenarrownursery [dot] com to order plants for delivery at my garden, or to get the full-color 2015 mail-order catalog.
(All photos except Acer pseudosieboldianum and top full-moon photo are from Adam Wheeler of Broken Arrow Nursery, used with permission.)
prefer the podcast?
ADAM WHEELER was my September 8, 2014 guest on the radio podcast. You can listen anywhere, anytime: Locally, in my Hudson Valley (NY)-Berkshires (MA)-Litchfield Hills (CT) region, “A Way to Garden” airs on Robin Hood Radio on Monday at 8:30 AM Eastern, with a rerun at 8:30 Saturdays. Get it free on iTunes, the Stitcher app, or streaming from RobinHoodRadio.com or via its RSS feed. Robin Hood is the smallest NPR station in the nation.