Trees worth a second look

American Forests, Wntr, 2005 by Ketzel Levine

Who knows why the Chinese pistache is conspicuously absent as a street tree in the Northwest? It's certainly not difficult to find in the trade, Perhaps the reason's been no more than an error in the Sunset Western Garden Book (since rectified), which insisted the tree was not hardy in the Northwest. In any event, expect to see more of it, thanks to the efforts of indefatigable hortheads, now lobbying to get this once-Chinese rarity into the urban mainstream.

HALESIA

A lone tree stands in a nursery in Portland with pendulous white bells ringing from its arms. You'd think someone might listen. But there it sits, unnoticed, choked by cherries and smothered by lilacs, with dogwoods baying to its lonesome tune.

Let's face it, if a plant trades in subtlety yet blooms in midspring, odds are good it won't get noticed. That's the only way I can explain why we don't grow more of the American native Halesia, which hit the shores of England decades before those rumors that we were using harbors to steep our tea.

The Carolina silverbell, H. carolina (syn. H. tetraptera), was the first halesia grown abroad. Commonly called silverbell, it's native not only to its namesake state but as far south as Florida and west to Oklahoma. Largely found on woodland edges, particularly along streams, H. Carolina--much like redbud and dogwood--is a classic understory tree.

In the landscape, though, this silverbell functions more as a huge, low-branched shrub with several trunks, forming an open, transparent structure almost as wide as it is tall. Its mature bark is strikingly veined in gray and black, and its pest- and disease-resistant leaves are pleasantly oval. Come winter, its showy, four-winged fruits (hence the name H. tetraptera) dangle like deflated punching bags, and are often fodder for birds.

But for 10 days in spring, the silverbell is no less than a benediction for humanity, with white, breathless bells that hand on angel hair-thin stalks and seem to enlighten anyone or anything beneath them. These simple, joyous flowers are the epitome of how I visualize faith: exquisitely simple and awesome in power.

Yup, they're that good. Like faith, however, they're fleeting; once they're gone, it's hard to believe they ever happened. Of course, one could say the same about Kwanzan cherries and lilacs, whose flowerless branches lack the slightest inspiration. What does last with a silverbell is a canopy of foliage that provides a perfect shelter for smaller rhodies and azaleas.

Having maxed out on sublimity, I now lack the adjectives to describe the later-flowering H. diptera var. magniflora, a selection of the two-winged (hence the name diptera) silverbell that is--at last!--increasingly varied in the trade. This often multistemmed variety has larger and more abundant blossoms than H. carolina (at one and a half inches, twice the size) and deeply cut, delicate lobes. The tree itself is slightly smaller, and its later bloom time gives it an edge on the competition.

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