Invasive Plant Management Program Loudoun County, Virginia

In Loudoun County, several types of invasive trees pose a threat to local ecosystems. Common invasive tree species include the Tree of Heaven, which produces extensive root systems that outcompete native plants, and the Black Locust, known for its rapid growth and ability to spread quickly. The Norway Maple and Bradford Pear are invasive trees that can dominate forest understories, displacing native species. Managing these invasive trees is essential to protect the health and biodiversity of local habitats.

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Dealing with invasive trees in Virginia requires a combined approach of cutting, herbicide application (specifically cut-stump or hack-and-squirt), and consistent monitoring for resprouts, ideally in late summer or fall. Key species include Tree-of-Heaven, Callery pear, and Mimosa. Crucial Tip: For Tree-of-Heaven, never just cut it down; it will send up multiple new shoots, so you must kill it while it is standing using herbicide. 

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Effective Removal Methods

• Cut-Stump Treatment: Cut the tree down and immediately apply systemic herbicide (like glyphosate or triclopyr) to the stump to prevent regrowth.

• Hack-and-Squirt: For larger trees, make downward cuts into the bark (hack) and spray herbicide into them (squirt).

• Basal Bark Application: Spray herbicide around the base of the tree (for smaller stems).

• Hand-Pulling: Effective for small seedlings, but ensure all roots are removed. 

  Fairfax County

Top Invasive Trees in Virginia

• Tree-of-Heaven (Ailanthus altissima): Requires precise herbicide treatment to prevent aggressive suckering.

• Callery (Bradford) Pear (Pyrus calleryana): Often spreads into fields; can be replaced through state-sponsored programs.

• Mimosa (Albizia julibrissin): Spreads rapidly; best removed before seeds mature.

• Princess Tree (Paulownia tomentosa): Fast-growing and competitive. 

  www.plantnovanatives.org

Best Practices and Tips

• Timing: Late summer through winter is generally the best time for treatment.

• Follow-Up: Consistently check the area for several years for new shoots.

• Safety: Use herbicides safely and consider hiring an ISA-certified arborist for large trees.

• Resources: Utilize resources from Blue Ridge PRISM or the Virginia Department of Forestry for identification and guidance.

• Replacement: Replace removed trees with native species to improve the ecosystem. 

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