How to Identify Male and Female Box Elder Trees

The box elder, Acer negundo, is a species of maple native to North America. It is also known as box elder maple and maple ash. However, unlike other maples, box elders are dioecious, which means each tree is either male or female. Both a male and female tree are needed for the trees to reproduce. Female box elder trees bear the seeds but both sexes have flowers.

Instructions

1. Look at the flowers of the tree. Female flowers share one stalk and form a dangling cluster. Males have one flower each on a thin, thread-like, drooping stalk. These stalks are grouped in clusters.

2. Examine the tree for fruit, called samara or key fruit. Thin "wings" are attached to the seed, often called a "helicopter." Female box elders bear fruit and males do not.

3. Check the tree for the presence of box elder bugs or their eggs in the summer. They will generally lay eggs on the female box elder.

References

• North Dakota State University Extension Office: Hortiscope: Questions on Box Elder
• University of Wisconsin Green Bay Herbarium: Trees Of Wisconsin Acer negundo, Boxelder
• University of Minnesota Extension: Boxelder Bugs
• University of Idaho Extension: Boxelder Bug