Pollen Type: Tree
Cross-Reactivity: Other Maples, Horse Chestnut
HS Allergy Extract: Boxelder
Genus/Species: Acer negundo
Common Names: Boxelder, Cutleaved Maple, Ash-Leaf Maple, Water Ash
Distribution: Throughout most of the United States.
Locations: Found near streams, lakes, floodplains, and low-lying wet areas. Abandoned fields and vacant/disturbed urban lots. It’s also commonly planted ornamentally along urban streets.
Pollination Method: Wind-pollinated
Pollinating Period: April & May
Description: Boxelder is a fast-growing, spreading, medium-sized maple tree which grows up to 70’. The leaves divide into three leaflets, or occasionally five or seven. Each leaflet is oval-shaped with a pointed tip with coarsely toothed edges. They are translucent light green and turn yellow in the fall. The small petal-less yellow-green flowers emerge just before the leaves appear. Boxelder is dioecious, meaning that male and female flowers grow on different plants. The male flowers grow in clusters of pollen-producing stamens on long drooping stalks. The female flowers grow in drooping clusters with separate flowers attached by short stalks along a central stem. Its seeds, called samaras, hang in long clusters and stay on the tree through winter. Nearly every seed is viable and can cover a disturbed area with seedlings. Because of this, it is sometimes considered a weedy or invasive species. Boxelder is the only maple that is entirely wind-pollinated, so it’s of greater allergenic importance.