Hidden Treasures of the Arboretum Pleasing Polyspora B Y W ALT B U B ELIS hile stroll- (135-99*A), which I noted ing along the down. Later, I consulted the W Lookout Loop Arboretum’s online interactive Trail in June, close to where map (http://depts.washington. it intersects with the New edu/uwbg/gardens/map.shtml) Zealand Forest, I came across and searched using the number. an attractive plant that I’d never The website gave me a name noticed before. It was a small, that I didn’t recognize: Polyspora erect, broadleaf tree, with speciosa (a synonym of Polyspora long, glossy, serrated leaves, large camellia-like kwangsiensis). flower buds, and ripening fruits that looked for Further research revealed the plant to be an the world like enormous green acorns. Peeling, evergreen member of the tea family (Theaceae) tan-colored bark also enhanced the display. that grows wild in the forests of China and The plant didn’t register with me, and the Vietnam and reaches 15 and 45 feet tall in its attached metal tag gave only an accession number natural habitat. Closely related to Camellia, 12 v Washington Park Arboretum Bulletin ABOVE: The leaves, flower buds, and acorn-shaped fruit of Polyspora speciosa. (Photo by Niall Dunne) OPPOSITE: Polyspora speciosa in bloom in the Arboretum in October. (Photo by Walt Bubelis) Gordonia is one of many plant genera with disjunct distribution (where related species are widely separated geographically) between the eastern United States and China. In the southeast- ern U.S., we have Gordonia lasianthus, the loblolly bay. This plant grows up to 70 feet tall and is used for cabinet wood. Just one other species of Gordonia is found in the New World, namely G. fruticosa, of the tropical forests of Central and South America. (Some botanists include the Franklin tree, Franklinia alatamaha, formerly of Georgia— but now extinct in the wild—as Gordonia, but Gordonia and Franklinia, the genus Polyspora research indicates that this plant is more closely contains about 40 species, all indigenous to East related to the Asian genus Schima.) and Southeast Asia. Polyspora species were originally thought The Arboretum’s digital map showed a speci- to be members of the genus Camellia, but once men of another species, Polyspora axillaris, quite seed pods are compared, you can see an obvious close to the P. speciosa. I returned to the site, and difference: Polyspora seed pods open to five sure enough, P. axillaris was there, just slightly valves, whereas there are just three in those of upslope and south of its cousin. Another attrac- Camellia. Another key difference is in the shape tive plant, native to China, it doesn’t grow as tall of the seeds: Polyspora seeds have wings, while as P. speciosa (about 20 feet at most) and produces Camellia seeds don’t. mostly entire, obovate leaves (shaped like an egg, but with the wide end at the tip). The Arboretum Specimens I asked Ray Larson, Curator of Living Collections Family Ties at UW Botanic Gardens, about the history of the Both plants have had recent name changes, Arboretum’s Polyspora specimens. He consulted having resided in the genus Gordonia, among the plant records and found that we procured others. Within the last 15 years or so, the roughly eight cuttings of three species of Polyspora from 40 Asian species of Gordonia were transferred to Rancho del Descanso Nursery in La Cañada, the genus Polyspora. California, in 1999. These cuttings were planted Winter 2016 v 13 LEFT: The foliage and flower buds of Polyspora axillaris. (Photo by Niall Dunne) RIGHT: Fullmoon ® Polyspora in bloom. (Photo courtesy Corinne Hollister) out in the Arboretum in 2002, but only two sur- depending on the species. The resemblance to the vived—the P. speciosa and P. axillaris I found along single flower of species Camellia—with their mul- the trail. A single specimen of another species, P. titude of yellow stamens in the center—is striking. chrysandra was among the original batch, but it A not-particularly-flattering common name for P. did not survive beyond the initial planting. axillaris is the fried-egg plant. I suppose, from a Polyspora axillaris is well established in culti- distance, a Polyspora in peak bloom can look a little vation, but our specimen doesn’t appear to be like it’s covered in eggs, over easy. doing so well, compared to the healthier-looking I returned to the Arboretum’s Polyspora P. speciosa. Perhaps it’s a hardiness issue, with specimens on a regular basis in the fall. In Polyspora speciosa rated for the cooler USDA Zone mid-October, Polyspora speciosa burst into bloom 7b and P. axillaris hardy to Zone 8b. Available in and flowered for about two weeks. As I write this, nurseries from Dan Hinkley’s Plant Collection in late October, P. axillaris has yet to bloom. An at Monrovia is a cultivar of another species, article I found by Professor David Creech at SFA Polyspora longicarpa, being sold as Fullmoon® Mast Arboretum, in Nacogdoches, Texas, says Polyspora (Polyspora longicarpa ‘MonSaPaRby’ that this species has a tendency to flower there PPAF). This plant is rated for hardiness Zones 7 in November or December. The bloom time to 11 and grows up to 12 feet tall. for Fullmoon® Polyspora blooms is marketed as The Arboretum plants are getting direct “winter or early spring.” sun for at least half the day, which seemed to Because of its handsome evergreen leaves and be helping them set numerous flower buds, bark, Polyspora is a plant for any season. Use it as a particularly in the case of P. speciosa. General focal point in a landscape large enough to accom- growing recommendations for the genus seem modate the eventual growth. Polyspora also looks to be the same as for camellias and loblolly bay. great in woodland settings with dappled light. Dan That is, partial shade to full sun in organically Hinkley also recommends Fullmoon® Polyspora for rich, slightly acidic, moist but well-draining mass plantings to create a tall, natural background soil. Growing the plant in partial shade will likely hedge or screen. If you don’t have room for the ensure more favorable moisture conditions but plant in your own garden—and you need a good may also decrease flower bud set. flower fix in the cool season—visit the Arboretum and track down our pleasing Polyspora. m Gorgeous, Late-Season Flowers If you’re lucky enough to locate a nursery specimen WALT BUBELIS is a Professor Emeritus in of Polyspora, whatever the name, you’ll undoubt- the Horticulture Department at Edmonds edly enjoy the blossoms. Large, five-petaled white Community College. He is also a member of the flowers appear in autumn, winter or early spring, “Bulletin” Editorial Board. 14 v Washington Park Arboretum Bulletin.