Box Elder Acer negundo Linnaeus    Synonyms: Acer negundo var. texanum, Boxelder, Negundo negundo.
Kingdom Plantae   >   Division Tracheophyta   >   Class Magnoliopsida   >   Order Sapindales   >   Family Sapindaceae   >   Genus Acer   

Status:

Box Elder is best known as a tree of moist bottomlands and flood plains, but it also tolerates drought and cold. Fast growing and hardy, it readily colonizes disturbed sites, vacant lots, and roadsides. It grows across most of Maryland, throughout much of the eastern U.S., and into the Midwest, Montana, and southern Canada. It was formerly planted widely as a windbreak and yard tree in the Midwest due to its cold hardiness and drought tolerance. It has a reputation as a weed tree, with its relatively short, irregular, poorly formed trunk that may divide near the ground into several main stems. Weak-wooded, Box Elder’s branches fall easy prey to wind and flooding, leaving the tree characteristically marred by stubs and hanging limbs. The tree is commonly able to bounce back after such damage, however, due to prolific sprouting from its branches and trunk. In the flood plains of the Potomac River gorge, it grows (along with American Sycamore, Silver Maple, willows, elms, and a few others) in the most flood-battered stretches, typically bouncing back post-flooding due to its prolific sprouting (Yanosky, 1982).

Description:

Among the dozen or so maple species native to North America, Box Elder is a bit of an oddball: Its leaves do not have the simple, palmately lobed shape typical of maples, but instead are pinnately compound, typically with 3-5 leaflets (which can resemble all too closely the three leaflets of Eastern Poison Ivy, but, in contrast to Poison Ivy’s alternate leaves and branches, Box Elder’s are opposite, like those of the other maples). The compound leaf explains another of Box Elder’s common names, Ash-leafed Maple. Box Elder also differs from its kin in having smooth, green twigs and in being dioecious, bearing male and female flowers on separate trees. Its flowers yield paired winged fruits (samaras) typical of the maple family, but in Box Elder, these ripen in September and commonly persist over the winter, whereas the samaras of our other common maples ripen and drop off in the spring.

Relationships:

Host plant for various butterfly species including Banded Hairstreak.

Host plant for various moth species including American Dagger Moth and Banded Tussock Moth (Database of World's Lepidopteran Host Plants).

Box Elder trees attract Eastern Boxelder Bugs, sometimes in large numbers, in the Spring.

There are 462 records in the project database.

View species at Maryland Plant Atlas

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Box Elder in Allegany Co., Maryland (5/9/2016). Photo by Kimberly Booth. (MBP list)

A Box Elder in Allegany Co., Maryland (6/2/2014). Photo by Kimberly Booth. (MBP list)

Box Elder in Anne Arundel Co., Maryland (7/15/2012). Photo by Bill Hubick. (MBP list)

A Box Elder trunk in Anne Arundel Co., Maryland (10/14/2013). Photo by Bill Hubick. (MBP list)

Box Elder sapling showing typical green color of young stems and twigs, in Montgomery Co., Maryland (2/11/2017). Photo by Bill Hill. (MBP list)

Box Elder in Prince George's Co., Maryland (7/16/2016). Photo by Wayne Longbottom. (MBP list)

Boxelder with seeds in Anne Arundel Co., Maryland (8/5/2012). Photo by Bill Hubick. (MBP list)

Box Elder in Harford Co., Maryland (6/24/2014). Photo by Jim Stasz. (MBP list)

Box Elder flowering in Kent Co., Maryland (4/1/2016). Photo by Nancy Martin. (MBP list)

Box Elder in Allegany Co., Maryland (5/11/2014). Photo by Kimberly Booth. (MBP list)

Box Elder in Allegany Co., Maryland (4/5/2017). Photo by Kimberly Booth. (MBP list)

Box Elder flowering in Harford Co., Maryland (4/16/2016). Photo by Bill Hubick. (MBP list)

Box Elder in Howard Co., Maryland (5/10/2017). Photo by Bill Harms. (MBP list)

Box Elder flowering in Kent Co., Maryland (3/26/2016). Photo by Nancy Martin. (MBP list)

Box Elder in Baltimore Co., Maryland (3/20/2019). Photo by Matthew Beziat. (MBP list)

Box Elder in Prince George's Co., Maryland (3/23/2019). Photo by Matthew Beziat. (MBP list)

Box Elder in Talbot Co., Maryland (3/21/2017). Photo by Jared Satchell. (MBP list)

The buds of Box Elder in Cecil Co., Maryland (4/7/2013). Photo by Jim Brighton. (MBP list)

A Box Elder sapling in Howard Co., Maryland (2/19/2017). Photo by Bill Hubick. (MBP list)

Box Elder growing in Washington Co., Maryland (6/22/2020). Photo by Mark Etheridge. (MBP list)

Box Elder in Baltimore Co., Maryland (4/23/2010). Photo by Bill Harms. (MBP list)

Box Elder in Anne Arundel Co., Maryland (3/12/2012). Photo by Bill Harms. (MBP list)

Box Elder in winter in Harford Co., Maryland (12/6/2015). Photo by Bill Hubick. (MBP list)

Box Elder blooming in Harford Co., Maryland (4/14/2018). Photo by Josh Emm. (MBP list)

Box Elder in Montgomery Co., Maryland (12/12/2015). Photo by Mike Ostrowski. (MBP list)

Box Elder in Allegany Co., Maryland (5/9/2016). Photo by Kimberly Booth. (MBP list)

Box Elder in Anne Arundel Co., Maryland (3/21/2011). Photo by Bill Harms. (MBP list)

Box Elder in Anne Arundel Co., Maryland (3/21/2011). Photo by Bill Harms. (MBP list)

Box Elder, which unlike other maples holds fruits into autumn, in Montgomery Co., Maryland (10/12/2013). Photo by Jane Hill. (MBP list)

The very trip of a Box Elder bud leafing out in Prince George's Co., Maryland (4/10/2015). Photo by USGS PWRC. (MBP list)

Box Elder growing in Frederick Co., Maryland (5/16/2017). Photo by Mark Etheridge. (MBP list)

Box Elder hosting a Leaf Curl (Taphrina species) in Howard Co., Maryland (5/1/2015). Photo by Richard Orr. (MBP list)


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