Black Walnut

Black Walnut

Juglans nigra

Juglandaceae (Walnut Family)

▲ ▼ leaves

▲ leaves with fall color and trunk bark

▲ bark (dark, gray-black, furrowed)

▲ fruit

▲ tree with fall color

Location on campus: along National Avenue, east of Craig Hall, Ellis Hall and Cheek Hall

Juglans nigra: Black Walnut:

• deciduous, alternate, pinnately compound leaves with 15-23 leaflets, often missing a terminal leaflet; leaflets pubescent, lanceolate, 2-4" long and 1/3 as wide with serrate margins
• twigs gray, terminal buds small & pubescent; twigs have chambered pith
• fruit is 2-3" diameter with a green, leathery husk with brown insides and nut is dark; husks do not split open at maturity to release nut
• brown with hard furrows, rounded-oval-shaped about 2" diameter
• medium to fast growing, with tan smooth bark when young followed by gray to black, furrowed bark with age
• grows 50-75' tall with equal width in open areas, 1/3 or less width in woodlands
• prefers fertile, moist, well-drained soils
• has hard, dark, valuable wood; produces allelochemicals that inhibit growth of herbaceous plants besides grasses under their canopy
• new disease of concern--“thousand cankers" disease, a fungal disease transmitted by a beetle
• disease found only in western U.S. states so far, but is feared to reach Missouri