When it comes to plant families, I have always been fascinated by odd bedfellows. To observe what genera would attend any given plant family’s summer reunion often reveals the intricacies of floral structure that botanists use to reason out plant relationships. One can be a good gardener without understanding and appreciating order, but it is endlessly entertaining to study it just the same.
The hydrangea family, Hydrangeaceae, is no exception. Though the type genus, Hydrangea, is obviously the most celebrated in an ornamental sense, there are numerous other genera of herbaceous perennials, vines, and shrubs that share its taxonomic digs. One of these is an evergreen shrub known as Dichroa febrifuga.
Dichroa is native to a large geographical area extending from Southeast Asia through the Indian subcontinent and including the Himalaya. Its leaves, a deep, glossy green, are carried in pairs along stems that can grow to five feet. Terminal heads of blue flowers appear in mid to late summer. (These do not possess the outer row of sterile florets we have come to associate with hydrangea flowers.) They result in a spectacular display of fleshy fruit of vibrant violet blue. The colorful fruit is held intact throughout the entire winter in our USDA Zone 8 woodland garden.
The genus name Dichroa, from the Greek dichroos (two-colored), makes reference to the variability of hue in flowers as well as fruit. I have encountered populations of this species throughout moderate elevations in Vietnam, Nepal, and western China where the fruit color varies from plant to plant, from near black to electric turquoise. Likewise, the flower color can vary dramatically from clone to clone. The specific epithet of febrifuga denotes its medicinal use as a febrifuge, or antifeverent. A tea made from its roots is still used to control the fevers associated with outbreaks of malaria.
Though I do not remotely suggest I am an authority on the genus, I believe, considering the significant variation found within its populations, there exists a quagmire in regard to its proper taxonomy. Dichroa versicolor (literally, “two colors with variable colors”) is encountered in commerce sometimes, but I believe it to be actually D. febrifuga.
My seed collections from a trip to eastern Nepal in 1995 resulted in plants with rather disappointing grayish pink flowers and lackluster fruiting effects. Fortunately, I had already come to admire this plant in my garden through the clone originally collected by Peter Wharton in the Guizhou Province. (Wharton is the curator of the David C. Lamm Asian Garden at the University of British Columbia Botanical Garden.)
Wharton’s dichroa remains one of the most asked-about plants in our garden, especially when displaying its fineries of fruit. Growing in a rather lax manner in a deeply shaded portion of our woodland, the panicles of glistening sapphire berries remain as effective in April as they had been upon ripening the previous October. This clone proves to be more rigidly upright if cultivated under brighter condition. Though this would be considered a nonhardy shrub in climates colder than Zone 7, I believe it would make a sensational containerized shrub if maintained in a cool, bright condition during the winter months.
Propagation by semi-hardwood cuttings in late summer remains as unchallenging as it is with hydrangea. Owing to its tendency to vary dramatically in appearance, propagation by seed is not advised. With that said, I have never had viable seed produced in my garden. For sources of Dichroa febrifuga, turn to page 84.
TYPE OF PLANT: evergreen shrub FAMILY: Hydrangeaceae ORIGIN: Nepal, southern China, Southeast Asia HEIGHT/SPREAD: 3-6 ft./3-6 ft. LEAVES: glossy, opposite, pointed elliptic, toothed FLOWERS: terminal panicles to 6 in. long and wide; color varies from white through pink and all shades of blue BLOOM PERIOD: mid to late summer FRUIT: metallic blue berries that last for several months HARDINESS: USDA Zones 7-10; Sunset Zones 4-9, 16-24, 26 EXPOSURE: shade to partial sun SOIL: acidic and humusy WATER NEEDS: moderate PROPAGATION: semi-hardwood cuttings in late summer PROBLEMS:, none cultural; flower and fruit color varies enough among plants in wild populations to suggest further classification could be made within the genus