Gardening with Deb: Aspens — A mountain town favorite

Deb Babcock/For the Steamboat Today
Deb Babcock

CSU Master Gardeners are available to answer your gardening questions 10 a.m. to 1 p.m. on Thursdays through the gardening season. Call 970-879-0825, email csumgprogram@co.r... or visit them in the Extension Office, 136 6th street.

Quaking Aspen (Populus tremuloides) is probably the tree most coveted by homeowners in Routt County.

Aspens are fast-growing, but relatively short-lived (20 years) trees attaining heights up to 50 feet. Cold-hardy but with poor drought resistance, aspens grow best in sunny locations at elevations of 7,000 feet and higher. They prefer moist, well-drained soil and good air circulation.

The beautiful white bark of an aspen is very thin and can be easily damaged by lawnmowers, weed trimmers and animals rubbing and clawing. When the bark is injured, insects and diseases tend to enter through the wound, which can shorten the life of your tree. A protective covering wrapped around the trunks of aspens for the first couple winters after they’ve been transplanted to your yard or garden can help prevent sun, wind and animal damage.

If wildlife is a problem in your yard, you might want to protect the tree’s buds and leaves during the spring and summer with repellent sprays until it grows tall enough to be out of the reach of browsing animals. But in my yard in west Routt County, the elk and deer tend to gnaw on the bark, so I needed to put a sturdy fence around my aspens to keep them from being damaged.

The best time to plant aspen trees is in the spring. This gives the tree roots all summer and fall to become established.

Aspens reproduce by both seeds and their root system. There are male and female trees, distinguished by the fuzzy catkins (of males) or cottony seed tassels (of females). Often, an original ‘mother’ tree is started by seed, then produces many suckers from its root system. These suckers can be a problem if aspens are planted in a yard or garden, but can be a great way to develop an aspen grove in an open meadow.

Aspens are prone to numerous problems, including cytospora canker, leaf spot, twig gall fly and other pests. A new product the CSU Extension office has found to be highly effective for insect control on aspens is the systemic Bayer Tree & Shrub Insect Control® containing imidacloprid, which lasts all season.

The trees are also susceptible to Marssonina Spot, which is a fungus, Marssonina populi, found in fallen leaves and brought on by wet weather and poor air circulation. If the infected leaves are not removed and destroyed, they could continue to infect the tree, causing defoliation, reduced growth and possibly the death of the tree. A fungicide applied in a timely manner can help stop the spread of this fungus and prevent further injury to the tree.

Aspens are not easy trees to grow and keep healthy, but the rewards of the work they entail are worth it in all the seasons: the glowing chartreuse leaves that burst out in the spring, the continual movement of the trembling leaves as summer winds blow through to the gorgeous yellows, the peach fall colors and the beautiful shadows and silhouettes in our winter landscapes. No wonder it’s a Steamboat favorite.

Deb Babcock is a Master Gardener through the CSU Extension Routt County. Questions? Call 879-0825 or email

Support Local Journalism

Support Local Journalism

Readers around Steamboat and Routt County make the Steamboat Pilot & Today’s work possible. Your financial contribution supports our efforts to deliver quality, locally relevant journalism.

Now more than ever, your support is critical to help us keep our community informed about the evolving coronavirus pandemic and the impact it is having locally. Every contribution, however large or small, will make a difference.

Each donation will be used exclusively for the development and creation of increased news coverage.