THE HUNT FOR RED SEPTEMBER

I have always been fascinated by red fall colour in produced by certain deciduous trees. My wife grew up in southern Ontario where the Carolinian forest bursts forth every autumn in a dazzling array of red and orange. Such colours are a rare site in the Canadian prairies where a short, dry summer and a long cold winter combine to limit the use of many tree species. In this article I would like to discuss three non-native tree species that have considerable potential in the prairie landscape.

Although its leaves are found on our flag and one cent piece, the Sugar Maple is largely foreign to landscapers and home owners in the Canadian prairies. Most of the Sugar Maple clones in the North American marketplace will not withstand the short seasons and harsh winters characteristic of the prairies. While some of these survival issues may be attributed to tender rootstock, often sourced from the eastern U.S., there is a real need for hardier selections of this species for use in the northern portions of zone 3.

Unity® is the first Canadian cultivar of Sugar Maple selected for the prairie climate. The parent tree was discovered in Morden, Manitoba by Rick Durand and Dr. Wilbert Ronald. Compared to other cultivars, Unity appears to be less susceptible to winter frost cracking, sun scald and dieback. Bare-root and container-grown material of Unity Sugar Maple is available in limited quantities in the prairie nursery trade.

In recent years, I have spent considerable time mapping Sugar Maple at its northwestern limits in the state of Minnesota. Although many range maps suggest this species reaches southeastern Manitoba, I do not believe this to be the case. The northernmost native Sugar Maple populations I have observed are approximately 75 miles southeast of the Manitoba border in the Red Lake area.

There is tremendous potential for this species to move into the prairie region.

Another promising trees for the future in the Canadian prairies may be the Freeman Maple named after Oliver Freeman a plant breeder at the National Arboretum in Washington, D.C. This naturally occurring hybrid between Red (Acer rubrum) and Silver Maple (Acer saccharinum) combines faster growth and tolerance to clay soils with outstanding red fall colour. The limitation to growing this species in zone 3 has always been the poor winter hardiness of available cultivars.

There are numerous cultivars of Freeman Maple on the market today, all of which originate in the United States. In Canada, the most commonly sold cultivar in recent years has been Autumn Blaze (Acer x freemanii ‘Jeffsred’). This cultivar has won numerous awards in the U.S., but it lacks the hardiness needed to thrive in the prairie provinces. Autumn Blaze serves as a tree for collectors and can survive in zone 3 when grown under sod in sheltered sites.

A newer introduction of Freeman Maple is Sienna Glen (Acer x freemanii ‘Sienna’). The parent tree was discovered in Lake Elmo, Minnesota (USDA Zone 4) by Dennis Heins. Compared to Autumn Blaze, Sienna Glen is reported to be less susceptible to winter frost cracking, sun scald and dieback. I have tested this variety in a landscape setting for two years and observed no winter kill or frost cracking. As I write this article in late August this specimen is already showing excellent fall colour in shades of orange and red.

Another tree species with potential to invigorate the prairie landscape is the Ohio Buckeye (Aesculus glabra). This tree is often overlooked by gardeners and landscapers who deem it to be exotic and unproven. As its name suggests, the native range of Ohio Buckeye is largely confined to forests of the central United States including Ohio, Indiana, Illinois and Missouri. Its survival in northern prairie regions can be attributed to its slow growth rate and the fact that most of its growth is confined to early summer.

As an ornamental, Buckeye is prized for its compound foliage, panicles of yellow flowers and the delightful combination of orange-red foliage and beige fruit in the fall. Buckeye is seed propagated and thus there is considerable variation among individual trees. Fall colour ranges from scarlet red to more subtle tones of orange and yellow.

Although Ohio Buckeye has typically been propagated by seed, North Dakota State University has recently named a clone cultivar of Buckeye known as Prairie Torch. This hardy selection has a dense, globose form with a mature height of 20-28 feet. It’s course, palmately compound leaves turn a brilliant orange-red colour in the fall.

I have started to assemble a collection of seedlings from mature Buckeye trees in southern Manitoba. My future breeding objectives for Buckeye would include early development of fall colour and prolonged leaf retention.

A final candidate in our hunt for a “red September” is the Northern Pin Oak (Quercus ellipsoidalis). This tree is almost unknown in the prairies, but is native across northern Minnesota. Northern Pin Oak is a member of the Red Oak group which includes Quercus rubra, Quercus coccinea. This group is recognized for their bristled leaves and outstanding red fall colour.

Like most oaks, Northern Pin Oak is slow growing and long lived. It also offers some tolerance to alkaline soils characteristic of the prairie provinces. Its native range encompasses an area from

Rick Durand of Prairie Shade Consulting selected Shooting Star Northern Pin Oak while canoeing in northwestern Ontario. This tree had spectacular red fall colour and was found at the northern limits for this species. However clonal propagation of this species has proven to be a challenge. Bud grafting on Bur Oak has shown some success, but differential growth rates of the scion and stock can result in problems later on.