Anyone who was drawn into gardening by tending plants on a windowsill knows the genus Schefflera. The glossy green, palmately compound leaves of tropical species like S. arboricola and S. actinophylla have long been cliches of the indoor landscape. But there are other species that offer the ornamental assets of the tropical forms, and the possibility of significantly greater hardiness.
The species that piqued my interest in potentially hardy members of the genus is Schefflera delavayi, a dramatic tree with enormous foliage, which I saw growing in the Asian woodland of the University of British Columbia Botanical Gardens in Vancouver. That this plant could make it through one of their USDA Zone 8 winters unharmed seemed illogical yet very exciting. Though that particular plant subsequently succumbed to an especially harsh winter, I received a clone of the species from Steve Hootman, plant explorer and co-director of the Rhododendron Botanical Garden in Federal Way, Washington. This specimen has sailed through every winter in our woodland for nine years–surviving temperatures in the single digits–and has grown to more than 18 feet. Its leaves are composed of five to seven leaflets that extend to one foot in length and possess a handsome slightly grayish cast. Evaluation of its hardiness at the Scott Arboretum of Swarthmore College (Zone 7), near Philadelphia, is initially very encouraging.
I observed my first schefflera in the wild at very high elevation in north-central Taiwan. It was S. taiwaniana (shown), and it was growing more than 11,000 feet with Japanese red pi (Pinus densiflorus). beautiful and finely lex tured evergreen, S. taiwa niana produces small round ed trees with compound foliage of narrow, deep green leaflets. The garden specimen at Heronswood, raised from my seed collections, now tops 15 feet and has been nonplussed by temperatures as low as 7o F.
The same year that I saw S. taiwaniana, I spent time in north Vietnam atop Fan Xi Phan, the highest mountain in southeast Asia. Numerous species of scheffleras grow there, all of which have thus far proven hardy in our Zone 8 garden. Schefflera alpina, for example, occurs at elevations over 10,000 feet and will probably prove as hardy as S. taiwaniana. It is more shrub than tree, growing to eight feet or less, with small, very glossy green foliage. It is a precocious bloomer, often producing flowers within two or three years of germination. Found slightly lower in elevation, S. hoi var. fansipaniensis produces an extra whorl of foliage in the center of each compound leaf along a rounded framework to 15 feet. This too thus far has proven to be completely unfazed by temperatures in the single digits.
The survival of a third Vietnamese species, S. petiolosa, surprised me because it grew at decidedly lower and milder elevations. Reddish fur covers its very large, deeply veined foliage when it emerges, then wears thin. I have mine planted in a sheltered position on the north side of my home; it has tripled in size in two years and continues to tick along. I will be delighted if my conservative predictions about its hardiness are proved false. Certainly additional species of gardenworthy scheffleras will be brought into cultivation in the years ahead. Whether or not a fantasy hardy species will ever grace a Chicago landscape, I will not venture a guess. I have been wrong too many times in the past. But the ossibility of such a victory is worth quite a number oflosses.
TYPE OF PLANT: a genus of evergreen shrubs, climbers, and trees FAMILY: Araliaceae ORIGIN: southeast Asia, the Pacific islands, Central and South America HARDINESS: tropical species, hardy to USDA Zone 12 and south, are most often grown as houseplants or annuals; species discussed here show potential for cooler climates, perhaps as far north as Zone 7 GROWN FOR: foliage, which is fine, long-stalked, and divided; some species show as many as 30 leaflets SOIL: humus rich but well drained EXPOSURE: sun or partial shade WATER NEEDS: moderate PROPAGATION: from seed or by hardwood cuttings in early winter