Fall Foliage of Quaking Aspen Trees
Quaking aspen trees (Populus tremuloides), with their golden-yellow fall foliage, are perhaps the dominant fall foliage tree of western North America. It is from this fall foliage standout that the ski resort of Aspen, Colorado derives its name. In the Rocky Mountains there are stands of these natural wonders that stretch for miles, their autumn gold perhaps punctuated here and there by an evergreen or two, as if for contrast. They are closely related to poplar trees, such as Lombardy poplar trees.
The origin of the name, "quaking" lies in the fact that the foliage of aspens shimmers or "quakes" when there is a breeze. This quality is due to the trees' flattened petioles, or leaf stalks. It's a poetic picture to imagine: A crisp blue sky, golden aspens and an autumn breeze, all working in concert to mimic the sun, shimmering across the deep blue seas.
As if their fall foliage weren't enough of a contribution, quaking aspens also have a lovely, whitish bark. Aspens usually reach a height of 20'-50', with a spread of 10'-30'. Plant them in full sun and in rich, well-drained soil. Like their willow-family relative, the pussy willow, quaking aspen trees bear catkins in the spring.
Quaking aspens have a wider range than any other tree of North America. They are absent from the Southeast in the U.S., but are found from Newfoundland and Alaska in the North as far south as central Mexico. But their greatest concentration is in Canada and the northern U.S. Indeed, this lover of the cold weather does best in zones 1-6.
Quaking aspens are quick to spread into disturbed areas, such as areas devastated by fire, and quick to put on some height. "Quick" is the salient term here for the landscaper, since quaking aspens are a good choice when you want a tree with some height, and you need it fast. However, the reason aspens take over a disturbed area so quickly is that their root systems are vigorous and aggressive. These powerful root systems will push up suckers everywhere. So be forewarned: you wouldn't want to plant this tree around pipes, for instance, nor is it one of the good plants for septic tank drain fields.
If you live in areas where beavers reside, you'll have to protect your quaking aspen trees. Beavers will go to work on aspens before any other tree. Ruffed grouse and other birds prize the aspen's buds in winter as a food source.