Common Name: Japanese cobra lily
Type: Herbaceous perennial
Family: Araceae
Zone: 5 to 9
Height: 1.00 to 2.00 feet
Spread: 1.00 to 2.00 feet
Bloom Time: April to May
Bloom Description: Brownish-purple
Sun: Part shade to full shade
Water: Medium to wet
Maintenance: Medium
Suggested Use: Rain Garden
Flower: Showy
Fruit: Showy
Tolerate: Heavy Shade, Wet Soil
Culture
Best grown in humus-rich, moist but well-drained soils in part shade to full shade. Needs consistent moisture. Does poorly in heavy clay soils. Plant tubers about 3-4" deep. May be grown from seed, but may take 3-5 years before plant will flower. Winter hardy to USDA Zone 6. In the St. Louis area, it should be planted in a sheltered location. Plants of this species are considered to be paradioecious (separate male and female plants in which the active fertile flowers which emerge on the spadix each spring may be of a different sex from year to year depending primarily upon the health and vigor of the plant). Young plants or plants experiencing stresses or female plants in the year following flowering will usually produce only fertile male flowers whereas healthy plants that are several years old and not subject to stresses often produce only fertile female flowers. In any given year, the fertile spadix flowers will be either male or female but not both.
Noteworthy Characteristics
Arisaema kishidae, commonly called cobra lily, is a tuberous woodland understory perennial that is native to certain forested areas near Osaka, Japan. It is closely related to the jack-in-the-pulpit (Arisaema triphyllum) that is native to eastern North America. Each tuber produces two leaves rising from a pseudostem to 15-24" tall, both of which contain 7-9 lanceolate green leaflets. Each leaflet has a showy central silvery-white stripe along the midvein and a toothed margin. A single flower structure emerges from the pseudostem in spring (April-May), each one consisting of a showy, brownish-purple, pitcher-like bract known as the spathe which subtends and encloses an inner, light brown, cylindrical, pencil-shaped flower spike known as the spadix. Tiny male or female flowers are located along the lower part of the spadix which rises slightly above the lip of the spathe in the shade of the arching and pointed spathe hood. Tiny female flowers are pollinated by insects, with the spathe and covering hood acting as a kettle trap. Plants go dormant in summer after flowering, except pollinated female flowers produce a vertical cluster of showy berries which ripen to bright red by late summer and become easily visible as soon as the spathe withers. Stalks, leaves, flowers and fruits give this plant a tropical aura. All plant parts contain calcium oxalate (same chemical as in Diffenbachia or dumb cane) and are poisonous.
Genus name comes from Greek words aris meaning "arum" and aima meaning "red", in reference to the red-blotched leaves found on some species.
'Silver Pattern' is a cultivar that features leaflets with a mid-vein silver stripe that is much larger than the stripe found on species plants.
Problems
No serious insect or disease problems.
Uses
Plant in groups for ornamental interest and to insure pollination of female plants will occur with subsequent production of showy red berries. Best left undisturbed in shady woodland gardens, wild gardens or native plant areas.