The Kentucky coffeetree (Gymnocladus dioicus) is a moderately fast-growing tree found in parks and along city streets. The tree is native to the Chicago area. Twigs are greenish to orange, very stout, with tiny buds. The compound leaves consist of 5-9 pairs of leaflets on a central stalk. Each leaflet is pointed and has wavy edges. Leaves have an alternate leaf arrangement and are often leafless more than half the year. Leaves turn bright yellow in the fall. The bark of young trees is bark pale gray, breaking into long shallow ridges with orange furrows (vertical grooves separated by ridges). Mature bark is dark brown and scaly. Female trees are characterized by having long red-brown, leathery pods with large rounded seeds. The native American Indians roasted the seed and also used grounded seeds to brew a beverage resembling coffee. The seeds; the seeds can also be eaten after boiling or roasting but raw seeds are poisonous. The wood is relatively soft but heavy and durable; the heart wood is light-brown with a red cast bordered by a thin creamy-white sapwood. The genus name is taken from the Greek “naked branch” as the tree appears in winter; its species name refers to the fact that male and female flowers grow on separate trees (dioecious).
Common name: Kentucky Coffee Tree, Kentucky Mahogany, Coffee-Nut Tree, Stump Tree, Luck Bean Tree
Scientific Name (family and order): Gymnocladus dioicus (L.) K. Koch (Fabaceae, Fabales)
Species Origin: Central and Eastern United States
New Jersey Status: USDA Native
Habit: 80’ – 100 high x 25 – 30’ wide; bole 3’. Tree has a broadly columnar habit sometimes spreading by suckers. The trunk often splits into multiple stems a few feet above the ground.
Habitat: Zone 3 – 8. Tree prefers moist, fertile, sheltered sites in sun or shade.
Trunk/Stem: Dark brown, rough with scaly plates.
Leaves: Deciduous, Bipinnately Compound, Alternate. Bipinnate and very large, 39” long x 24” wide, each leaf bears up to 6 leaf pairs of opposite pinnae and the pinnae each bear up to 7 pairs of opposite leaflets which are ovate, taper-pointed at the tip and up to 3” long, untoothed. Leaflets emerge as bronze becoming dark green above (adaxial); bluish beneath (abaxial); with maturity they become smooth on both sides. The leaflets are oppositely placed; the end leaflet is often absent but a pair of leaflets remain at the base of the pinnae (rachis). The leaflets drop in the fall leaving the naked rachis attached to the shoots. The petiole base has a swelling (pulvinus) Leaflets turn yellow in fall.
Flowers: Dioecious. The individual flowers are greenish white, small, fragrant about 1” across, with 4-5 petals with the same number of sepals; inflorescence is a 12” long panicle or raceme often hidden by leaves; male panicle 4” long; unisex flowers on separate plants in late spring to early summer.
Fruits and seeds: A large leathery, dehiscent hanging pod, 10” long which is glaucous green at first then ripening to a red-brown, persisting even into the winter. The seed pod remains closed throughout the winter; it contains up to 9 seeds set within a sweet tasting pulp.