Sask. Perennial Society
Although the Japanese maple doesn’t stand a chance of overwintering on the Canadian prairies, the Amur or ginnala maple (Acer ginnala) is about the same size but is is tougher than nails. It is easily pruned to form a small graceful tree and turns a brilliant scarlet in autumn.
It is native to China, Japan, Siberia and Manchuria, including the Amur River valley, from which it gets its common name. The species name, from the Greek ginnos (“a small mule”), refers to the plant’s size and toughness.
Fast growing, it can be left as a large shrub, but is more pleasing when pruned to a single trunk, to form a small rounded tree of about 5 m (15 ft.) tall. The flowers, produced in May, are greenish-white and inconspicuous. The leaves are three-lobed, with the middle lobe longer than the side lobes. The leaf veins and petioles are red, as are the paired, winged seedpods or samaras of late summer that ripen to a straw color by fall.
Several selections are available. ‘Flame’ is slightly smaller than the species (4.5 x 4.5 m/13 x 13 ft.), has a rounded form, a single trunk, and as its name suggests, intense orange-red fall color. ‘Royal Crown’ is a University of Minnesota introduction with clump form and resistance to iron chlorisis (yellowing leaves with green veins), a common problem in prairie soils.
Although they tolerate partial shade, Amur maples prefer well drained soil with a pH below 7.0 and full sunlight for the best fall color. Older varieties are susceptible to lime-induced chlorosis in very high pH soils (i.e. many prairie soils), but some of the newer introductions have been selected for resistance to this problem. Once established they are amazingly drought tolerant.
This is an excellent choice for smaller urban yards or massed in larger spaces, as an informal (untrimmed) hedge, or for screening. The seeds, retained through winter, are a treat for grosbeaks and other birds.
The Manitoba maple or box elder (Acer negundo) has been a part of the prairie scene forever. Familiarity sometimes breeds contempt, but without this tree, life would have been considerably more difficult for early settlers. It still has its place in larger landscapes.
Acer is the classical name for maple. The word negundo is more convoluted; from the common name for the chaste tree which has similar foliage. The common name box elder comes from the similarity of the whitish wood to that of the boxwood. As the other common name implies, Manitoba maple is native to the prairies and has been used extensively as shelterbelt, shade and boulevard trees.
It is fast growing, and able to attain a height of 10 to 13 m (30-40 ft.) or more during its 60-year life span. The leaves resemble those of ash – compound with three to seven irregularly leaflets.
Male and female flowers are on separate trees with only the female trees producing seeds. The female flower is greenish-yellow in drooping clusters. The male flower is a dense red tassel. Both appear before the leaves. The seed pods are winged and V-shaped and persist into winter.
‘Baron’, introduced from the Morden, Manitoba, Agriculture Canada Research Station, is a male (seedless) selection of about 12 m (40 ft.) with an upright, oval to round growth habit and bright yellow fall foliage.
‘Durone’ (Ventura) is a hybrid of Tartarian and Amur maple developed by Rick Durand. It is hardy to zone 2 and resistant to iron chlorosis (6 x 5 m/20 x 15 ft.).
Manitoba maples are adapted to full sun and a wide range of soils. They do not do as well in shade. Problems include sensitivity to 2,4-D (in shelterbelts when adjacent fields are sprayed) and their attractiveness to aphids that excrete “honeydew” onto decks, picnic tables and vehicles below the tree canopy.
In spite of their faults, they are invaluable for large landscapes and tough sites. Although their size precludes them from smaller urban lots, they are excellent for shelterbelts, farmsteads or acreages, and second-to-none for tree houses and as a kids’ climbing tree. As well, they provide food and cover for a wide variety of birds and may be tapped for maple syrup.
Sara Williams is the author and coauthor of many books including Creating the Prairie Xeriscape, Gardening Naturally with Hugh Skinner and, with Bob Bors, the recently published Growing Fruit in Northern Gardens. She continues to give workshops on a wide range of gardening topics throughout the prairies.
