Thursday, September 12, 2002
Steamboat Springs Every fall, the brilliant golden leaves of the aspen trees in the mountains inspire many local homeowners to plant a few of these beauties near their houses. Quaking aspen (Populus tremuloides) is probably the tree most coveted by homeowners in the Steamboat Springs area.
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 of 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 buds and leaves during the spring and summer with netting or repellent sprays until it grows tall enough to be out of the reach of browsing animals.
If you're transplanting an aspen from the forest (be sure to purchase a permit) or from a nursery, dig the planting hole two to three times the width of the rootball. Then position the tree at the same level as it was growing in the ground or container. Add back soil to halfway up the hole and water. Then add the rest of the soil to completely fill the hole and water again. Apply a mulch about 3 inches deep to help retain the water in the soil.
The best time to plant aspen trees is in the spring. This gives the tree roots all summer and fall to become established. The next best time to transplant aspens is in the fall after the leaves have dropped and buds appear on the branches. When planting in the fall, be sure to monitor your tree to ensure it has adequate moisture throughout the fall and winter. If the winter is dry, you may need to water your aspen once or twice.
Aspens reproduce by both seeds and its 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. But for many gardeners, the joy these trees bring are worth the extra care it takes to keep them healthy and beautiful.
Deb Babcock is a Master Gardener through the Colorado State University Cooperative Extension office in Routt County. Questions? Call the CSU Cooperative Extension office at 879-0825 or e-mail firstname.lastname@example.org.