Scientific Name
Acer negundo ‘Flamingo’
The box elder is the only maple native to North America with compound leaves, which typically consist of three or five leaflets, though vigorous shoots may occasionally produce seven or nine. This tree is native to nearly all of the lower 48 states, the Canadian prairie provinces and parts of Mexico. In Colorado, it is native along the Front Range.
Box elder has long been considered a weedy and invasive tree and is often scorned because it hosts the underappreciated box elder bug, which feeds on its seeds. However, in some of the most difficult planting sites, it remains one of the few reliable options. And while invasive plants are often thought of as a problem imported into the United States, box elder itself has become established as a nuisance species in many parts of Europe, as well as in Australia, China and Argentina.
In Colorado, box elder usually grows to around 40 feet tall, though some specimens have exceeded 60 feet and developed trunks measuring an astounding 84 inches in diameter, a full 7 feet across. As with all maples, the foliage is arranged in opposite pairs on the twigs, and the fruit is a double-winged samara containing two seeds. Unlike most other maples, however, box elder trees are either entirely male or entirely female, meaning male trees never produce seed. The ‘Flamingo’ cultivar has been described in some horticultural references as male and in others as female, but because no seed has been observed on the Regis tree, the male designation seems most likely. Box elder trees grow quickly but are not especially long-lived, and only rarely survive to 100 years of age.
Several box elder cultivars have been developed over the years, many featuring some form of variegation, or irregular coloration mixed into the normal green of the leaves. One such cultivar is the Regis tree, ‘Flamingo,’ which is known for its new shoots and leaves that emerge pink before maturing to green with white variegation. This tree has shown signs of “reversion,” meaning much of the canopy returns to solid green foliage by midsummer, though some albino shoots still appear, especially near the trunk. Pruning certain branches can sometimes encourage more vigorous new growth and restore some of the original variegation, though the height this tree has reached makes that difficult in practice.