Updated: Jul 21
If there was ever a botanical plant name to cause confusion, it is this one. This is of particular consequence to me, because West Valley College has an old specimen on campus (shown), and its coloring is throwing me off. One side, tending to be in more shade, is green (leaf below), whereas the more exposed leaves have a reddish tint (leaf at left). In Autumn, the leaves turn bright red if they have not already toasted in the sun. At first I thought this tree was as Sunset describes, A. palmatum 'Dissectum', which used to be named A. palmatum 'Dissectum Viridis' for the green leaves. However, the green turns gold in fall, so this option can be dismissed.
As I began my research, the names quickly altered from one source to another. Here are the configurations I have seen from the sources I rely upon most:
Sunset: Acer palmatum 'Ever Red' ('Dissectum Nirgum') (p. 130)
UFEI: Acer palmatum 'Dissectum Atropurpureum' (with a common name ever red Japanese maple, suggesting the cultivar noted above)
Missouri Botanical Garden (MBG): Acer palmatum var. dissectum 'Dissectum Atropurpureum'
North Carolina State Extension: Acer palmatum var. dissectum
J.D. Vertrees (1987): Acer palmatum dissectum atropurpureum (p. 70)
Oregon State University: Acer palmatum var. dissectum atropurpureum
The references to "ever red" do not really apply to our campus specimen, since there tends to be more green than red. MBG seems to be going out of their way with a little redundancy, so I am curious to know how this name was finalized, despite some explanation on their website. Simply adding dissectum, as in NC State's identification, misses the point about the red leaves. Our specimen has both green and red leaves, so which is it?
Based on this list, Oregon State's identification seems to be the most scientifically correct, but I started with J.D. Vertrees for his clear explanation.
One difficulty with seedling-producing plants is the variation in the degree of "redness" which will result. The plants may vary from a decided green cast of the foliage to the other extreme of dark maroon or black-red. All may come from the same parent seed tree. I have purchased young plants of "diss. atropurpureum" which varied from a rusty green to a very acceptable red.
Given the age of the specimen on campus, Vertrees' observations suggest that we have a seedling of this variety. And "variety" is the key component to the name. Sunset clearly defines Japanese maples into two distinct types, those of the more common nondissectums that exhibit what we typically think of as a maple leaf, and dissectums with deeply cut leaves giving them a lacy appearance. Therefore, I think Oregon State has it right, and that is what I will label this tree. Certainly, if we find new information about this specific tree, or clarification regarding botanical names, this information could be washed. But for now, the varietal will remain.
Oh, and great tree...you'll love it.
West Valley College Campus Location: Acer palmatum var. dissectum atropurpureum
President's Office (west face)
Long: 122° 0'39.54"W
Botanical Name: Acer palmatum var. dissectum atropurpureum
Acer: Traditional Latin name for maple
Palmatum: Palmate leaves, as in the palm of your hand
Dissectum: Cut or divided leaves
Atropurpureum: Having purple leaves
Common Name: Cut-leaf Japanese maple
Family Name: Sapindaceae
Origin: Japan, Korea, and China
Positioning: Forest edge, small spaces, container/planter, patios, pathways
Garden Themes: Woodland, shade, Asian-inspired, rock, water, moon, autumn, winter
Uses: Specimen, bonsai, accent, border, sculptural
Type: Deciduous shrub or tree
Form: Mound, spreading, weeping
Size: 10' to 12' wide x 8' to 10' tall
Outstanding Feature(s): Summer and fall texture and color (leaf), sculptural value
Bark: Light green to gray, furrowed with age.
Shape: Palmate, lobed
Margin: Deeply serrate
Color: Medium to dark green or dark red turning bright red/orange in fall
Flower: Spring. Inconspicuous
Fruit: Summer. Samara, green to red.
cultural requirements, tolerances & problems
Sunset Zones: A3; 2b-10, 12, 14-24
USDA Zones: 5-8
Light: Full sun in cool regions to partial shade (fall color performs best with afternoon shade)
WUCOLS SF Bay Area Hydro Zone: Moderate
Texture: Sand, loam, well-composted
Moisture Retention: Moist but well-drained
pH: Highly acidic to slightly alkaline
Tolerances: Deer, rabbits
Branch Strength: Medium
Insects: Aphids, borers
Disease: Verticillium wilt, armillaria, root rot
Momiji and Kaede: These words are both used by the Japanese to indicate the species and cultivars of Acer. Academically, the word "Kaede" is more correctly applied. However, in horticultural use both "Momiji" and "Kaede" are often used. There seems to be no distinct separation in the use, although most often "Momiji" is applied to those maples such as A. palmatum and its cultivars which have leaves with deeply serrated lobes. Most other maples are termed "Kaede."
~ J.D. Vertrees referencing Hideo Suzuki
citations & attributions
Breen, P. "Acer palmatum var. dissectum atropurpureum." Oregon State University, College of Agricultural Sciences, Department of Horticulture. Accessed on June 28, 2021, from https://landscapeplants.oregonstate.edu/plants/acer-palmatum-var-dissectum-atropurpureum.
Missouri Botanical Garden. "Acer palmatum var. dissectum 'Dissectum Atropurpureum." Missouri Botanical Garden. Accessed on June 28, 2021 from http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=241795.
Norris Brenzel, K. (Ed.). (2012). The New Sunset Western Garden Book. New York: Time Home Entertainment, Inc.
NC State Extension. "Acer palmatum var. dissectum." North Carolina State University, Raleigh. Accessed on June 28, 2021, from https://plants.ces.ncsu.edu/plants/acer-palmatum-var-dissectum/.
Urban Forest Ecosystems Institute SelecTree. "Acer palmatum 'Dissectum Atropurpureum Tree Record." 1995-2021. Cal Poly State University, San Luis Obispo. Accessed on June 27, 2021. https://selectree.calpoly.edu/tree-detail/70.
Vertrees, J.D. (1987). Japanese Maples, Second Edition: Momiji and Kaede. Portland: Timber Press.
Water Use Classification of Landscape Species. "WUCOLS IV Plant List." University of California, Division of Agriculture and Natural Resources, Davis. Accessed on June 27, 2021.
All photos by TELCS.