How to Identify and Remove Boxelder

Common Name	Boxelder, ashleaf maple
Botanical Name	Acer negundo
Plant Type	Tree
Mature Size	30–50 ft. tall, 30-50 ft. wide
Soil Type	Moist
Hardiness Zones	2–10 (USDA)
Native Area	North America
Toxicity	Toxic to horses

Boxelder Invasiveness

Boxelder trees in the landscape very often begin as volunteer seedlings that sprout from seeds from nearby trees. It is a very fast-growing tree that can reach a 1-foot-diameter trunk within 10 years. Its wood, however, is brittle and breaks easily from wind and ice.

Suckers appear just about anywhere, often in hard-to-reach or inconvenient locations such as near the foundation of a house or a septic system. If not controlled, boxelder chokes out other, more valuable native species. Therefore any suckers and volunteer saplings that have spread via seed dispersion should be removed promptly. Even after a boxelder has been cut down, it can resprout from the stem for many years, which adds to its invasive character.

Another compelling reason why boxelder is a shunned tree is that it is the main food source for boxelder bugs, which can become household pests. Boxelder bugs are winged insects, about 12-inch long. They are black with orange or red markings, including three stripes behind the head. The insects overwinter, often unnoticed, in the warmth of homes, in sheds, or garages, and emerge in the spring. Adult boxelder bugs can fly up to two miles so any boxelder trees in the neighborhood are a potential source for an infestation.

What Does Boxelder Look Like

A moderate-sized tree with an irregular crown, the boxelder has leaves that are somewhat smaller and shaped differently from other maples. The leaves are typically light green with three lobes (or sometimes five) that look like individual leaves. Unlike many maples, the leaves of the boxelder do not have a waxy surface and instead a somewhat puckered texture.

A telltale characteristic of boxelders is the green color of the young branches, stems, and twigs.

Boxelder is a dioecious plant, which means individual trees produce male or female flowers, but not both. The inconspicuous flowers appear in April or May. Male flowers are red or yellow and resemble threads while the female flowers are green and located near the base of new shoots; they usually appear a bit later than the male flowers. The flowers tend to drop after storms and leave quite a mess on cars and streets. Later the female tree produces seeds in the form of clusters of “helicopter” samaras which mature in the fall and remain on the tree until the early spring.

The fall foliage of boxelder is unremarkable.

How To Get Rid of Boxelder

The earlier you remove boxelder seedlings that have sprouted from seeds, the better. as they can be difficult to remove once they are established. Hand-pull or dig out the entire seedling with all its roots.

As the saplings get older, removing boxelder becomes too deeply rooted to remove so applying a broad-spectrum systemic herbicide might be your best option. Either cut the tree at the base and promptly brush the surface with herbicide concentrate, or isolate the tree by placing a plastic bottle with the bottom removed over the seedling and spray it with herbicide. One word of caution though. The roots of boxelder often grow entwined with the roots of other trees. Applying a broad-spectrum systemic herbicide such as glyphosate, triclopyr, or 2,4-D bears the risk of killing a desirable tree.

If a young tree is too deeply rooted to dig out, try cutting it back and taping it with duct tape to prevent sun exposure. This can weaken the root system and make it easier to remove over time.

In any event, because boxelder resprouts so vigorously over a long time, you need to keep an eye on it and repeat the treatment as needed.