The Maples of Oregon

I would love to show you a photo of a young boy holding an enormous leaf of the “Oregon maple,” Acer macrophyllum, but it was in our Portland newspaper and therefore the photo is protected under copyright laws. The Oregonian does not freely share even though they have featured me twice for free: once for my “Ghost” series of Japanese maples, and the other for my botanical and horticultural book collection. There would be absolutely no harm in sharing this photo, but I already tip-toe along the nebulous line of plagiarism, and I do so in nearly every blog.

In any case it got me thinking about the three species of Acer native to Oregon: circinatum, macrophyllum and glabrum. I was also prompted by the flowering – for the first time – of the original A. macrophyllum 'Mocha Rose', a chance seedling that I discovered about 13 years ago. No credit should be given to me because it was impossible to miss the strongly pink foliage in a batch of green seedlings that were being grown for rootstock. I've even witnessed truck drivers, on more than one occasion, get out of their smelly cabs to inspect 'Mocha Rose' for it is planted near the loading dock. Maybe its wrong for me to stereotype truck drivers, but they seldom show any interest in our tree collection and what we stuff into their 53' trailers. 'Mocha Rose' is such an unusual color I guess – would salmon-pinkbe close? My grandfather Gerald's wife, Harriette, was visiting a few years ago, and I pointed out that the selection had no official cultivar name. She suggested Mocha Rose as the rose foliage in spring turns to a light brown. That is an unusual color too, but it has absolutely nothing to do with burning or death.

I have grown other cultivars of A. macrophyllum, such as 'Seattle Sentinel' and 'Kimballiae', but the USDA zone 6 (-10F) limits sales. Also I think that gardeners fear that the trees will become huge, and it's true that they do. 'Seattle Sentinel' was noticed, named and introduced by Brian Mulligan in 1951, then director of the Washington Park Arboretum. It was found on a street in Seattle, and I hope that it is still there. Please Seattle, help me find it. One of its propagules exists at the west side of the Arboretum near the parking lot of the Japanese Garden.

Acer macrophyllum 'Kimballiae' is a more bushy form and the leaves are deeply cut to the base. It has been known since 1940 and the original is also in the Washington Park Arboretum.

We have two variegated (green/white) forms of macrophyllum: 'Santiam Snow' and 'Mieke'. The former was found near the Santiam pass east of Salem, Oregon, and was discovered, named and introduced by Heritage Nursery of Oregon. I bought a few but I have yet to trial them out in the full sun. I blogged about 'Santiam Snow' last summer, and the next day friend and blog reader Dave Kemper was driving home – on a road he has taken thousands of times – when he spotted a variegated branch on a “Big Leaf maple.” He brought in a gnarly portion and we were successful with a few scions. At this point in April the light yellow color has not developed into white. I wonder that if I had not blogged about 'Santiam Snow', would ol' Kemper have ever noticed his variegated tree? It was named for the nick-name of his wife Marieke. Variegated macrophyllums have been known for a long time, and De Beaulieu in An Illustrated Guide to Maples lists 'Variegatium' from 1893 in Germany, and says, “Old specimens of this cultivar progressively lose their coloring.”

Not surprisingly there are golden forms of Acer macrophyllum, with Dancing Oaks Nursery of Oregon listing 'Aureum'. I have not seen it and don't know if it can withstand full sun. They also list 'Elynor's' but they have no photo and it is one that I have never heard of before today. I have another golden macrophyllum – 'Golden Riddle'– but it is also in the greenhouse, untested outside. Due to the shady nature of the greenhouse, its outdoor color remains unknown.

Acer macrophyllum is a friendly species that I know well – I have rested in their shade since childhood. I was embarrassed a couple of years ago when the world's champion was toppled in a windstorm.* It was only an hour's drive away from me, but I never knew that the whopper existed there. One Sunday I paid homage to the venerable giant, for it grew along the highway in the town of Jewell, Oregon, population about 100. At first I passed it without notice, but I recruited two mossy denizens for information. They scratched their heads in unison, then called up the town wag. Certainly Flo would know, and indeed she thrice shouted out loud, “It's along the road, right past the school.” I didn't require the boys to repeat, but they did anyway. I easily found it...sadly lying in the weeds, not so great anymore.

Acer macrophyllum 'Jewell'

Acer macrophyllum 'Holznagel Tree'

There are a number of impressive macs in the area of soggy Jewell, which is about 20 miles from the ocean and receives double the rain as my nursery. Sometimes they stand alone in a pasture, other times they hover over a two-story house. Just outside of town is the Holznagel tree, nicely fenced off. I don't know anything about H. or why a huge tree bears his name, and I didn't want to trouble Flo with more questions. Anyway the tree is certainly older than anyone in town, and it exists grandly no matter its name.

Archibald Menzies

David Douglas

The Acer macrophyllum species was first scientifically described by Archibald Menzies of the Vancouver expedition. Seed was later collected by Lewis and Clark, and in 1826 David Douglas introduced it to England. Hillier describes it as “A large tree with handsome, very large, shining, dark green leaves, which turn a bright orange in autumn.” I have never seen the bright orange color; in Oregon it can turn a fantastic yellow though. The major freeway west of Portland (Hwy 26) features a two-mile stretch of woods that is dominated by Acer macrophyllum with their yellow precocious spring blossoms and dramatic fall color. Then one enters into a long tunnel where the kids sing “Flamingooooooooo”...and then you are suddenly in Portland.

While the route into Portland is awesome– a word I rarely use – I think my favorite location to wander among the macrophyllums is on Washington's Olympic Peninsula at the Hall of Mosses in the Hoh Rain Forest. A loop trail of about one mile is full of maples – circinatum and macrophyllum – and they are fantastically festooned with moss and ferns. The fern in the photo above is the “western sword fern,” Polystichum munitum, and it happily thrives on the moisture of the maple's bark. In dryer areas like the Columbia River Gorge, the macrophyllums host the “Licorice fern,” Polypodium glycyrrhiza.* You can easily pull a piece from the tree, then you clean the roots and nibble at them. You just nibble, and don't eat, and your taste buds will indulge in a strong licorice flavor that lasts for a few minutes. It is sad to ponder that the vast majority of Oregonians don't know about the treats in the woods, but I was sure to pass along the experience to my children, just as my father did for me.

*The genus name Polypodium is from Greek polypodiun for poly– “many” or “more” and pod pous– “foot.” Glycyrrhiza is from Greek glukurrhiza meaning “sweetroot,” as glukkus means “sweet” and rhiza means “root.” The candy known as licoriceis made from Glycyrrhiza glabra, an herbaceous perennial legume native to southern Europe and Asia. Licorice extracts are used in herbal and folk medications, and the Chinese considered it to be a stimulant; excessive consumption, however, can lead to adverse effects, so don't let your kids get carried away with the black ropes.

Acer circinatum received its specific name from Latin for “circular,” referring to the round-leaf shape. It is native to western North America from British Columbia to California, and in places the “Vine maples” can grow in impenetrable stands. I have seen forests – with circinatum as an understory – ravaged by forest fire. Everything is burned to the ground, but the vine maples quickly resprout. During the summer the leaves are a preferred browse for deer and elk, while squirrels and chipmunks eat the leaves and seeds. We must trap for squirrels at the nursery because at night they can eat a good number of Japanese maple one-year grafts; that are already sold, I might add. A. circinatum is in the palmata Section along with A. shirasawanum, A. japonicum and A. palmatum, and they can all be used interchangeably when grafting. I found it curious that Vertrees in Japanese Maplesincluded the circinatums even though they are not “native” to Japan. His reason: “Although Acer circinatum is not a Japanese maple, it is included here for comparative purposes because it is a close relative of the Japanese species...” Masayoshi Yano in Book for Maples resists the temptation. Vertrees continues by suggesting that a land bridge “connecting Alaska with east Asia allowed plants and animals to migrate between the two continents.”

Acer circinatum 'Monroe'

There are a number of circinatum cultivars, but oddly the 2014 Hillier Manual of Trees and Shrubslists only 'Monroe' which was found in the Willamette National Forest, Oregon in 1960. Somebody dumbly named it 'Monroe' for the finder Warner Monroe, a college professor of philosophy. My largest specimen is planted at the edge of the woods down by the creek, and it measure about 15' tall by 15' wide. Back to Hillier, the Manual is like a bible for me, but my main gripe is how the English can be so insular, kind of like the Chinese who assume that they are at the center of the Earth. Hillier's list (2014) of palmatum cultivars contains 'Dissectum Nigrum', 'Dissectum Ornatum', 'Dissectum Palmatifidum' and 'Dissectum Variegatum', most of which no one grows anymore. It would have been easy to copy from the Vertrees/Gregory 4^th edition. I was surprised that Acer circinatum 'Burgundy Jewel' was not included. I was one of the first to grow it and I sent it to England (Junker Nursery) a long time ago. It was even featured in The Garden, a monthly publication from the Royal Horticultural Society. 'Burgundy Jewel' was discovered by Gordy Halgren of Peacedale Nursery in Washington state, not in Oregon as stated by the Vertrees/Gregory book. We grow ours in full sun, as in shade the leaves remain greenish. It is a stout, vigorous cultivar which we propagate onto palmatum rootstock.

The first Vine maple cultivar that I acquired was 'Little Gem' which was discovered as a witch's broom mutation in Stanley Park, Vancouver B.C. by plantsman Alleyne Cook. He found at least one other mutation which simply went by the name 'Alleyne Cook'. I never met the man, but I bought a portion of his book collection, and inside of one of E.H. Wilson's books was a photo of Mr. Cook with a pretty girl. I wondered if she was his wife, or ?, but why was it hiding in an old plant book? Back to 'Little Gem', be sure to give it plenty of room. My 35-year-old specimen is planted in the Blue Forest, and it is now 7' tall by 12' wide, and yes it bulges into the road. I fear for its safety from the aforementioned knucklehead truck divers.

Acer circinatum 'Sunglow'

Acer circinatum 'Sunny Sister'

I suppose my best circinatum introduction is 'Sunglow'. Peter Gregory concludes his description of it, “It is very different from any other A. circinatum cultivar and is highly desirable.” Well, thank you Mr. Gregory, but there are six others much like it. Seven dwarf seedlings were discovered by the late Floyd McMullen of Portland, Oregon. He never named them, but I have two of the originals, so I introduced 'Sunglow' and 'Sunny Sister'. I never met Mr. McMullen, but he gave his seedlings away, two of them going to my Grandfather Gerald. I have never seen the remaining five, nor know where they are. 'Sunny Sister' is the more vigorous of the two, growing at about twice the rate of 'Sunglow', and the former withstands summer heat better as well. Every year 'Sunglow's' coloration is different, depending on how soon it gets hot, and I must confess that it can look dreadful by August – since mine is in full sun. I don't grow many 'Sunglows' anymore because they are susceptible to powdery mildew, a fungus named Podosphaera xanthii. I have read that milk, diluted with water at 1:10, is effective in the management of mildew, and it can be sprayed on the leaves at the first sign of infection, or as a preventative. Maybe I should get a cow.

The tiniest circinatum of all is 'Baby Buttons'; and ok, maybe it is the best of my Vine maple introductions. It too was of witch's broom origin, and its leaves are often only a half inch in diameter. As with 'Little Gem' and 'Sunglow', 'Baby Buttons' will be more vigorous in a greenhouse, leading the first-time visitor to conclude that it's not so dwarf after all. But plant one out and you will see. Our first propagated plants (about 2008) are only 18” tall by 18” wide, and they receive fertilizer. A cute specimen resides in a pot at the Rhododendron Species Foundation in Federal Way, Washington, gracing the front of the conservatory. At the nursery the plants are lushly green at the end of this April, and I pray that a late frost won't ruin the fun.

Acer circinatum is perhaps most famous for its vibrant autumn color, although in some countries – like England – they do not have the correct conditions for it to perform at its peak. The same can be said for the “Sugar maple,” Acer saccharum, which is largely a non-event in England. The fall color on circinatum can range from straw-yellow to orange, red and purple. A hike up Hamilton Mountain on the Washington side of the Columbia River Gorge illustrates the variation of color. At the bottom of the mountain the vines exist in lush soil conditions, especially along the stream. Their autumn color is a rich yellow. As one ascends, near the top the boney soil is more sparse in nutrients, and the circinatums glow with orange to red.

The same can be said with our final Oregon maple species, Acer glabrum ssp. douglasii. In lush conditions fall color will be yellow, but higher up on sparse soil the fall color is orange-to-red. This variation is most evident on Silver Star Mountain in Washington state. I have one tree in the collection at Flora Farm, and I planted it there out of a sense of obligation, that maple-man Buchholz should have all three of the Northwest species on his property, and it stands at the edge of the woods...and is totally unnoticeable. I know of no cultivars of glabrum, and I feel that most of the plant world wouldn't care if it disappeared altogether.

Amelanchier alnifolia

Amelanchier alnifolia

Acer glabrum is native to western North America, but it has a large range that extends east to Nebraska and south to Arizona and New Mexico. There are a number of varietiesor subspecies, and I have never understood the distinction between those two botanical terms. In any case Acer glabrum var. glabrum is the “Rocky Mountain maple,” but then so is Acer glabrum var. diffusum. Acer glabrum var. or ssp. torreyi is endemic to northern California. Acer glabrum var. or ssp. neomexicanum is native to New Mexico. You won't be tested on the above because neither of us knows anything about them, and all I have seen is ssp. douglasii which comes from Oregon and Washington and was seen by David Douglas. I don't really champion Acer glabrum as a landscape plant, but the shoots and seedlings can be collected and eaten fresh or cooked like asparagus. The “Douglas maple” was used by Native Americans to cure nausea, and the wood and bark were combined with Amelanchier alnifolia to improve the healing process of a woman following childbirth, and also used to increase lactation. That won't be of any benefit to me of course, and I'll remain content with my one specimen at the edge of the woods.

Attractive females are welcome to visit me in spring, summer or fall, and I can lead you to a place above Wahkeena Falls in the Columbia River Gorge where all three of Oregon's native maples thrive, literally touching leaf to leaf. To my knowledge they never hybridize, with circinatum in the section Palmata, macrophyllum in the section Lithocarpa, and glabrum in the section Glabra. All three are beautiful at their time, just as Wahkeena was known as a beautiful Indian maiden. All said, I wish to live in no other state more than Oregon.