By Ray Larson, Curator

In honor of the annual Elisabeth Miller Memorial Lecture on September 10 in Meany Hall, this month’s plant profile features one of her favorite trees, and perhaps the plant most associated with her:  Acer japonicum ‘Aconitifolium.’

At the UW Botanic Gardens, we have a grove of 6 planted in the Dorothy McVay Courtyard.  These trees were included at Mrs. Miller’s suggestion when Iain Robertson developed the garden design for the courtyard in the mid-1980s.  Betty Miller’s famous garden just north of Seattle includes over two dozen of the trees, which are among the very best small trees for texture and outstanding fall color.

They begin coloring in late July and slowly build to a crescendo of fiery reds ranging from flame orange to deep maroon.  They are among the most reliable trees for fall color in the Pacific Northwest, and generally at their peak in mid-October.

As an added benefit they have small but showy flowers, which appear in early spring right before the leaves unfurl.  The shape of the leaves gives the tree its common name, and the scientific name refers to their resemblance to monkshood foliage (Aconitum).   They grow well in part shade to sun, with longest and best fall color appearing in more sun.  One of the best small trees for urban gardens, either singly or in a grove.  This is the most commonly grown Acer japonicum, but the UW Botanic Gardens has several other varieties, including impressive specimens of A. japonicum ‘O-isami’ and A. japonicum ‘Takinogawa’ in the Woodland Garden.  Acer japonicum ‘Aconitifolium’ received an Award of Garden Merit (AGM) from the Royal Horticultural Society in 1984.  It is reputedly hardier than other forms of Acer japonicum, and is rated down to USDA Zone 5.

Common name:  Fernleaf fullmoon maple
Family:   Sapindaceae
Location:  McVay Courtyard at the Center for Urban Horticulture
Origin:  The species is native to mountain forests of Japan, Manchuria and Korea.  According to Arthur Lee Jacobson’s North American Landscape Trees, this form was introduced to cultivation around 1888 by Parsons Nursery in Flushing, NY.
Height and spread:  Generally 12-18’ high and as wide
Bloom time:  Late March-early April
Bloom color:  dark red, and showy for a maple