CSFS Recommends Water-Sipping Trees for Colorado Landscapes

June 6, 2003

The height of the busy spring planting season is just a couple of weeks away, and the drought, damaging spring snowstorms and watering restrictions have left many landowners wondering if they should plant trees this year. The answer is a resounding yes, and the sooner the better.

"The damage and loss of trees from the recent spring snowstorms is significant, but the moisture has created an environment that is good for planting, so it would be wise to begin the replacement process as soon as possible," said Keith Wood, assistant staff forester, Community Forestry Division, Colorado State Forest Service.

When deciding what to plant, it’s important to remember that Colorado is still in a drought—and that drought is a recurring event—so it’s best to plant trees that will conserve water and withstand Colorado’s rigorous climate and harsh environmental conditions.

"Trees that can withstand dry conditions are often termed drought tolerant. However, it may be more appropriate to say that a majority of tree species that escape damage during dry periods are drought avoiders," said Wood.

Some trees truly are drought tolerant, which means they are able to withstand significant water depletion in their leaves and stems before damage occurs. However, most species possess some genetic adaptation to survive drought by retaining water within their leaf and stem tissues. Adaptations include the ability of roots to extract large amounts of water from the soil due to a higher root-to-shoot ratio; reduced leaf surface due to rolling; folding and shedding leaves; limited transpiration from the leaf surface during dry conditions; and a thick, waxy cuticle on the leaf surface that minimizes transpirational losses of water vapor.

When replacing trees or adding new trees to the landscape, the Colorado State Forest Service recommends the following tree species, which have demonstrated the ability to avoid and tolerate dry conditions.

Hackberry, Hawthorn, Kentucky Coffeetree, Black Walnut, Upright and Spreading Junipers, Bristlecone Pine, Pinyon, Limber Pine, Mugo Pine, Ponderosa Pine, American Plum, HoptreeOrnamental Pears (avoid Bradford), Gambel Oak, Bur Oak.

Amur Maple, Tatarian Maple, Wasatch Maple, Ohio Buckeye, Horsechestnut, Serviceberry, Western Catalpa, All Green Ash Cultivars, All Honeylocust Cultivars, Golden Raintree, Apples and Crabapples, Colorado Blue Spruce, Austrian Pine, Southwestern White Pine, Scotch Pine, Chokecherry, Canada Red Cherry, Mayday Tree, White Oak, English Oak, Japanese Pagoda Tree, Japanese Tree Lilac.

For a complete list of drought-tolerant species and cultivated varieties and advice on how to manage woody plants before, during and following a drought, visit www.watersaver.org or http://www.ext.colostate.edu/drought/woody.html.