Aspen trees (Populus spp.), including quaking aspen (Populus tremuloides, USDA zones 1-6) with leaves that tremble on flexible leaf stalks in the breeze, produce spectacular fall foliage. In addition to adding beauty to landscapes, the aspen serves as a succession tree.
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With its seeds and underground suckers, aspens quickly fill in areas where vegetation was lost, such as to fire, and thus the tree helps prevent erosion in many wild areas. In the home landscape, however, aspen roots spreading is more often troublesome than helpful. Controlling aspen roots and stopping them from spreading into your garden, lawn or other unwanted areas requires diligent care and clever landscaping.
Barriers to Stop Aspen Roots
Aspen shoots appear from both the trunk and roots as a form of vegetative reproduction. Trees anchor and spread quickly with this particular adaptation. One strategy to prevent root spread is the use of barriers. Commonly constructed of plastic or metal, thick sheets are installed vertically in the ground along the tree's perimeter, such as between the aspen and your garden.
Because aspens have shallow roots that go down only about 12 inches deep, a barrier approximately 24 inches deep should keep the majority of roots from sprouting new shoots in your garden. You can find tree barriers at Home Depot, Amazon and Walmart. Keep an eye out for any roots that may grow over the barrier, and pull them as soon as you notice them.
Mowing Out Aspen Sprouts
Aspen roots are notorious for appearing in lawns, much like small weed sprouts. Before they grow longer and thicker, mow your lawn to remove the roots. Use your lawnmower's bagger to store and discard the root pieces away from your lawn and garden.
Maintain sharp mower blades to cut quickly through the roots, as well as your long grass. This strategy works well during your lawn's active growing period, depending on the species. Lawns generally require mowing spring, summer and fall, at least once a week. This mowing frequency keeps overzealous aspen roots under control.
Aspen Tree Growth
Growing up to 50 feet tall with a 25 foot spread, aspen trees produce root systems that grow well past their drip lines in search of nutrients, oxygen and moisture. As a result, your nearby garden may have small sprouts emerging from the soil. Diligently pull or prune these growths away with garden shears before they grow too large to cut by hand.
Deep Watering and Pruning Aspens
Aspens use their spreading roots as a self-preservation tactic, especially when under stress. To prevent stress, maintain a healthy tree by allowing the soil to dry between irrigation sessions. When you do water, however, thoroughly saturate the entire root system to force the roots downward for moisture absorption.
Aspens that are not severely pruned or disturbed at root level through cultivation have less sprouts emerging from the ground. They do not waste energy on vegetative spread if the mother plant is healthy. Start mulching around your aspen, as well, to conserve soil moisture so roots remain deep within the ground.