Drake elm offers great shade

Published 6:00 pm Sunday, August 14, 2016

Summer continues to coast right along with its hot weather and afternoon showers. The grass is green, the knockout roses are thriving, and the pine trees are dropping needles for fall landscape beds. In a short time, fall will be in the air. What a refreshing thought following a high temperature-high humidity season.

Another tree to consider in the landscape is the Chinese or lacebark elm (Ulmus parvifolia). It is an excellent shade tree and possesses several characteristics which make it most favorable for many landscape applications. This desirable semi-evergreen tree is native to China, Japan, North Korea and Vietnam. And, the Drake elm (a cultivar) forms a graceful, spreading, rounded canopy of long, arching, and somewhat weeping branches which are filled with two to three-inch-long, shiny, dark green, leathery leaves. Some specimens grow in the typical vase-shaped elm form, while others appear to grow horizontally instead of upright like a tree.

In the cooler part of its range of growth, the leaves provide various shades of red, purple, or yellow coloration in the fall. The tree is semi-evergreen to evergreen in the southern extent of its growth range and its showy, exfoliating bark reveals random, mottled patterns of grey, green, orange, and brown which add textural and visual interest.

The Chinese elm species can reach 80 feet in height but Drake only grows to about 40 to 50 feet tall with a slender trunk and crown. It makes an ideal shade, specimen, street or parking lot tree if it is trained and pruned to allow for vehicular and pedestrian clearance underneath. It has small, leathery, lustrous green single-toothed leaves and produces small, inconspicuous flowers in the fall followed by a samara fruit. The trunk offers a handsome, flaking bark of mottled greys with tans and reds, giving rise to its other common name, the lacebark elm.

The Chinese elm is highly resistant (but not immune) to the Dutch elm disease which has been devastating to the American elms throughout the country. It is moderately resistant to the elm leaf beetle (Xanthogaleruca luteola), but is susceptible to Elm Yellows disease.

When purchasing the Chinese elm, select trees with branches spaced along one trunk. Seek nurseries who understand how to prune and train this tree for its multiple landscape uses. Otherwise, lots of pruning and trimming of low drooping branches will be necessary on a regular basis in your garden.

Trees with trunks less than two inches in diameter will require proper staking and select pruning to prevent leaning and blow-over because of their heavy crown and unstable root system. Nursery people will train these trees to a single, straight trunk by staking at an early age. Leaving branches on the lower trunk during this training period will encourage caliper development of the lower trunk. Also, older trees are complimented by periodic light thinning or pruning to expose the attractive trunk and branch structure.

Be sure that all selections were propagated from cutting; otherwise, you may not be getting a Drake elm. Do not confuse these with the Siberian elm (Ulmus pumila) which is inferior to the Chinese elm and should not be planted. To be certain that you are getting the right elm, look for the small, reddish-brown, pointed leaf buds and cinnamon patches of bark of the Chinese elm. Siberian elms have round, black leaf buds and are less desirable.

The root system consists of several very large-diameter roots which can grow to great distances from the trunk. These shallow roots can occasionally lift and crack sidewalks and get into sewer lines causing damage. However, proper planting location away from sidewalks and sewers (also foundations) will help minimize this problem. Keep this tree in your urban tree and residential planning program because of its positive qualities. The Chinese elm is among the top urban and residential trees on most recommended tree lists in the south and midwest.

The Chinese elm will grow in full sun on a wide range of soil conditions, adapting easily to extremes in pH or moisture levels, and tolerates cold temperatures, urban heat, and wind stress. They can adapt to the drought and extremes of urban sites quite easily. However, these trees will be most healthy when grown in a moist, well-drained, fertile soil and are very suitable as street trees, lawn trees, parking lot island plantings, and in other confined soil spaces. Propagation is by cuttings or grafts.

Many cultivars are available for size and form including Catlin (dwarf), Drake (small, dark green leaves), Dynasty (smooth, dark grey bark, smaller leaves and vase-shaped), Frosty (small, white-margined leaf which can return back to green), Emer I or Emerald Isle (dark green foliage with bright orange, grey and brown exfoliating bark), Golden Rey (dense growth with yellow new foliage color which deepens to golden yellow in the fall), Pathfinder (single trunk with broad, upright branches and rich red fall color), Sempervirens or Pendens (rounded canopy with weeping and spreading branches), and True Green (glossy, deep green leaves with a rounded, evergreen canopy). Frontier is an autumn flowering species, whereas most other elms flower in spring.

Other cultivars include Central Park Splendor, Everclear, Burgundy, Burnley Select, Chessins, Churchyard, Cork Bark, D.B.Cole, Dwarf Weeper, Ed Wood, Elsmo, Emer II or Emerald Vase (Allee), Emerald Prairie, Garden City Clone, Geisha, Glory, Hallelujah, Harzam (Harrison), Hokkaido, Jade Empress, King’s Choice, Littleleaf, Lois Hole, Matthew, Milliken, Nire-keyaki, Ohio, Orange Ribbon, Prairie Shade, Red Fall, Sabamiki, Sagei, Seiju, Select 380, State Fair, Stone’s Dwarf, Taiwan, The Thinker, Todd, Bosque, Ware’s, Yarralumla, Yatsubusa, and Zettler (Heritage).

Most of the elms make great shade and avenue trees, and the Chinese elm is one of the best. It is a sustainable landscape tree and very favorable for the environment. As a fast growing and adaptable tough tree, Drake is an excellent choice as a shade tree for all sizes and shapes of landscapes and gardens.

Seagle is a sustainability associate, golf environment organization (Scotland), agronomist and horticulturalist, CSI: Seagle (Consulting Services International), professor emeritus and honorary alumnus, Abraham Baldwin Agricultural College, and associate editor of The Golf Course, International Journal of Golf Science. Reach him at csi_seagle@yahoo.com.