A Short Guide to Aspen Trees and Their Care

A Short Guide to Aspen Trees and Their Care

How to Care For Your Aspen Trees

Aspen trees are a beloved symbol of Colorado, thriving in higher elevations and providing shade in summer, vibrant colors in autumn, and beautiful white bark in winter. However, caring for aspens in Denver can be challenging due to the heavy clay soils and hot lowland weather. In this short guide, we’ll share some tips for keeping your aspen trees happy and healthy.

Keeping Aspens Happy in the City

Aspens for sale in Denver are typically transplanted from the mountains. To recreate their natural environment, it’s important to plant them in a berm of sandy loam soil. This raised area should be mulched and connected to an irrigation system to maintain slightly damp soil. Keeping the berm away from foot traffic will help prevent soil compaction. Despite careful care, aspens typically live for about 25 years in a city landscape.

Aspen Shoots

If you have aspens on your property, you may notice little shoots sprouting up from the ground. These shoots are clones of the parent tree and can become new aspen trees if not cut down. Mowing them when necessary is recommended, but avoid using chemicals to kill them since they are still part of the original tree. In fact, there is an aspen grove in Utah that is 106 acres in size, 80,000 years old, and considered the largest living organism on earth.

Aspen trees’ bright white bark is not only aesthetically pleasing but also serves a purpose. During harsh winters, when food is scarce for wildlife in the mountains, the white bark produces sugars that become a last resort food source for deer and elk.

Common Aspen Tree Pests in Denver

Aspen trees in Denver can be susceptible to various pests and disorders. Here are some of the most common ones and how to address them:


A Short Guide to Aspen Trees and Their Care

Aphids can be a nuisance, blackening leaves with their honeydew in late summer and fall. Applying dormant oils in winter can help kill the eggs, while insecticide soaps and systemic injections can control aphids during the growing season.

Oystershell Scale

A Short Guide to Aspen Trees and Their Care

Oystershell scales are insects that look like oyster shells and can cause damage to the bark of aspen trees. Applying dormant oils in winter can help kill the eggs, and summer oils and crawler sprays can control the insect during its nymph stage. It’s important to note that scraping off the scales should be done carefully to avoid damaging the tree.

Poplar Twiggal Fly

A Short Guide to Aspen Trees and Their Care

The Poplar Twiggall Fly can cause lumpy twigs on aspen trees. In most cases, it’s best to let local birds and parasitic wasps control this tree pest.

Other pests that attack aspens include Aspen Leaf Miners, Sawflies, Western Tent Caterpillar, and Poplar Borer.

Common Aspen Tree Ailments in Denver

Fungi and mineral depletion are common factors contributing to ailments in aspens. Here are a few examples:


A Short Guide to Aspen Trees and Their Care

Cytospora cankers are often the cause of denuded aspen trees. Winter drought stress can make thin-barked trees like aspens susceptible to canker diseases. Removal of affected limbs is the recommended treatment, while prevention through proper watering and fertilization can help the trees’ natural defenses ward off this disease.

Marssonina Leaf Blight

A Short Guide to Aspen Trees and Their Care

Marssonina leaf blight is a fungus that grows in yard debris and causes yellow-ringed dark spots on aspen leaves. Raking up leaves in the fall and thinning aspen stands can help prevent the growth of this fungus.

Iron Chlorosis

A Short Guide to Aspen Trees and Their Care

Iron chlorosis occurs when aspens struggle to take up enough iron from Denver’s clay soils, causing yellowing leaves. The injection of chelated iron products can help control this disease.

Other ailments commonly found in aspens include Leaf and Shoot Blight, Ink Spot, Septoria Leaf Spot, and Leaf Rust.

5 Ways to Prevent Aspen Disease in Denver

To ensure the health of your aspen trees, it’s crucial to seek the expertise of tree care professionals. Contact the tree experts at Ross Tree Service to schedule inspections, treatments, trimmings, and other services for your aspen trees. Tips Tree Planting is committed to providing the best care for your beloved trees in Denver. Call 303-871-9121 or click here to fill out a tree service request form.

A Short Guide to Aspen Trees and Their Care