Culture
Grow in fertile, moist but well-drained soils in full sun to part shade. Intolerant of drought and hot summer climates. Keep soils consistently moist. Best sited in locations protected from cold winds (particularly in spring). Winter hardy to USDA Zone 6 or 7, but may be grown further north into USDA Zone 5 where it may die to the ground in winter with roots surviving to produce new growth in spring.
Noteworthy Characteristics
Decaisnea fargesii is an upright, multi-stemmed, deciduous shrub that is native to woodlands, thickets, mountain slopes and ravines in western China, Bhutan, NE India, Myanmar, Nepal and Sikkim. This shrub typically grows to 20' tall and as wide. It is ornamentally grown in some areas for its long odd-pinnate leaves, its monoecious flowers in drooping racemes and its exceptional metallic blue bean-like fruit pods. Each leaf (to 36" long) has 13-25 ovate to elliptic leaflets that are dark green above and glaucous green beneath. Drooping racemes (to 18" long) of apetalous, bell-shaped, green to yellow-green flowers bloom in summer. Although individual flowers are not particularly showy, the large racemes in bloom are interesting and attractive. Flowers give way to the piece de resistance: cylindrical, bean-like seed pods (to 4" long) that ripen to blue in fall. It is these fruits (actually fleshy follicles) that distinguish this plant. Common names of deadman's fingers, blue sausage fruit, blue cucumber shrub and blue bean tree all convey the general message that the fruits are quite interesting and unique. Fruits will split open at maturity to reveal a large mass of seeds imbedded in edible pulp. Lepchas (aboriginal inhabitants of Sikkim) relish this fruit, but it is not eaten much outside its native geographic range. Decaisnea was originally considered to have only two species, D. insignis and D. fargesii, with the only difference between the two being that the former had yellow green fruit and the latter had blue fruit. Today, some experts continue to list two different species (see Royal Horticultural Society), but others have combined both species into D. insignis (see Flora of China).
Genus name honors Joseph Decaisne (1807-1882), director of the Jardin des Plantes, Paris, eminent French botanist and horticulturist of Belgian origin.
Specific epithet honors Pere Paul Guillaume Farges (1844-1912) who lived in China and discovered this plant. He collected and recorded plants in China from 1867 until his death.
Problems
No serious insect or disease problems.
Uses
Best in shrub borders or woodland gardens.