Foliage of ‘Kelly’s Gold’

A. negundo ‘Falmingo’

Box elder (Acer negundo) is a native fast-growing and suckering medium-sized tree (USDA hardiness zones 4b-8).  Branches are weak wooded and easily damaged in wind and ice storms. Box elder grows almost anywhere in any average soil, medium to wet, and in full sun. The species fails on a shady site. This weedy maple is tolerant of drought and flooding, perfect choice in fence rows, abandoned fields, and in vacant urban lots.

A mature tree typically grows 30-50 feet tall with an irregular rounded crown. Flowers and leaves emerge from mid-April to late May, depending on region of the country. Dioecious trees, either male or female, bear yellow-green wind-pollinated flowers in mid-spring. Compound foliage comprised of 3-5 leaflets. Non-showy flowers appear in pendant clusters in spring on separate male and female trees. In late summer winged nutlets (samaras) ripen on female trees and often hang on well into winter. Seedlings will likely become a nuisance weed in gardens. Fall color is often a blah yellow but in some years may surprise.

Box elder is a high maintenance tree. The tree is plagued by boxelder bugs, which do not harm the tree but can be a serious nuisance pest to homeowners as bugs invade houses in fall and winter months. Tree is also susceptible to aphids and borers. Anthracnose, powdery mildew and canker are occasional disease problems. Planting it in some cities is illegal. There are lots of better trees to choose from.

Cultivars have been developed with variegated or colorful foliage, improved plant habit, and better fall color. These 5 cultivars are mostly available from on-line nurseries:

‘Flamingo’ – 30-35 feet tall, variegated leaves (light green, with white and pink), a male clone (seedless).

‘Kelly’s Gold’ – 15-20 feet tall, bright yellow new growth, a male clone (seedless).

‘Sensation’ –  30 feet by 25 feet tree, reddish foliage in fall, a male clone (seedless).

‘Variegatum’  – 40 by 25 feet tree, variegated leaves (white margins), a female clone.

‘Aureomarginatum’-small 30 foot tree with dark green/white variegated foliage, female clone.