Boxelder, Manitoba Maple, Ash-leaved Maple                        A-ser ne-GOON-do

• Broadleaf deciduous tree, 30-50 ft (9-15 m) high, broad, rounded, often multi-stemmed.   Leaves opposite, compound (ash-like, pinnate), usually 3-5 leaflets which are obovate to elliptical, terminal leaflet has a long stalk (petiolule), margins entire or serrate, leaf surfaces may be tomentose (pubescent) at first, bright green above and lighter green below; in fall, yellow-green and brown.  Dioecious - male and female plants; female flowers yellowish green, hang in slender, pendulous clusters (racemes), 15 cm long; each male flowers is on a long, thin stalk, these are grouped in clusters (corymbs), mostly yellow, but some may be pink.  Fruit is in long, narrow clusters, the pair of wings of each fruit forms an angle of less than 60^o; fruit often persist into winter.
• Sun.  Native to steams banks, lakes, and swamps.  Performs well out of its native habitat.  Usually short-lived.  Male trees preferred because of the absence of fruit (seeds).
• Hardy to USDA Zone 2 (very hardy)    Native to nearly the entire eastern U.S., southern Canada and into Mexico.
• Several cultivars are available:
  • ‘Flamingo’  -  variegated leaves (light green, with white and pink), a male clone (seedless).
  • ‘Kelly's Gold’ -  new growth is bright yellow, may become yellow green in summer, a male clone (seedless).
  • ‘Sensation’ -  reddish foliage in fall, a male clone (seedless).
  • ‘Variegatum’  -  common selection, variegated leaves (white margins), a female clone.
• Caution for horse owners: Seeds of Boxelder apparently are the cause of a disorder called Seasonal Pasture Myopathy (SPM), an equine muscle disease which is fatal in over 90% of cases. See: http://www.cvm.umn.edu/umec/SPM/
• negundo: apparently from the native name of Vitex negundo (Chastetree), because of a supposed similarity of the leaves.
• Oregon State Univ. campus: just east of Callahan dorm.