Juglans cinerea is a tree to 30 m tall, short lived, not more than 75 years, bark gray-brown with smooth rather shiny ridges; taprooted but root system more fibrous than J. nigra; upper margin of leaf scar densely hairy.
Leaves alternate, pinnately compound, leaflets 7-17, opposite (Petrides 1988).
Flowers monoecious, catkins, male on last years shoots, female on current years growth, female flowers open before male, wind pollinated May-June.
Fruit egg-shaped, with “snout,” longer than wide, Sept.-Oct. apparent on leafless trees in fall; seed oblong, very rough, requires overwintering and burial for germination, eaten and dispersed by squirrels. Young fruit destroyed by grackles.
Wetland status: FACU+.
Frequency in New York City: Infrequent. Likely to be extinct in NYC soon (see below).
Habitat: Open areas, stream banks, moist to dry, rocky soil. Shade intolerant.
Notes: Produces allelopathic substance, juglone, especially from roots and fruit husk, toxic to other vegetation. Young stems and fruit attacked by butternut curculio (Conotrachelus juglandis); trees subject to butternut decline/canker caused by the fungus Sirococcus clavigignenti-juglandacearum (Deuteromycotina, Coelomycetes) which kills bark. This fungus was only discovered in the 1970 and is the major cause of severe population declines of butternut. More disease prone than J. nigra. Very susceptible to fire and storm damage (Burns and Honkala 1990; Sinclair et al. 1987).