In the Garden: Snowbell, Not to be Confused with Silverbell

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By Charles Kidder

Weeping Styrax
Weeping Styrax

If you were paying attention last month—’hem, ’hem—you’ll remember that we looked at Halesias or silverbell trees. I left you with the teaser that we might be looking at the similarly-named snowbell tree. So here goes.

Snowbell tree is the common name for the Styrax genus, although sometimes storax is used as a common name just to confuse things a bit. To muddle things even further, silverbells and snowbells are related plants, with similar flowers. But not to worry. None of this will be on the final.

With over 130 species, Styraxes are fairly widespread over the Northern Hemisphere, with the greatest concentration in East Asia. Certain species in Sumatra, Java and Thailand are tapped to produce benzoin resin, used since antiquity to produce perfumes, incense and medicines. The incense is sold in Europe as an air freshener, Le Papier d’Armenie. Burning it produces benzene and formaldehyde, but it is reportedly less toxic than other air fresheners. (“As long as you only use it every few days and air out the room in between.” Uhh, maybe not…) Also, historically styrax incense was burned in Southern Arabia during the harvest of frankincense. Reportedly only this smoke would drive away the nasty snakes that lived around the Boswellia plants. Again, not so sure I want to use this stuff as an air freshener. If any of you are familiar with Le Papier d’Armenie, I would be interested to hear your take on it.

Those that are found in American gardens are all small trees grown primarily for their white pendulous bell-like flowers. Most commonly seen in the landscape are two Asian species, Styrax japonicus and S. obassia. The former goes by Japanese snowbell, while the latter is known as Fragrant Snowbell. Japanese snowbell may grow to 20-25 feet and will flower in early to mid-May. It does not have any significant fall color, but the bark is an interesting, smooth gray with brown fissures. Some of the better cultivars: ‘Carillon,’ a small weeping tree; ‘Emerald Pagoda,’ with both larger leaves and flowers and a more upright habit; and ‘Pink Chimes’ with, of course, pink flowers.

As the name implies, the Fragrant Snowbell produces sweet-smelling flowers. They hang in a grouping known as a raceme and open over a three-week period. Leaves on this species are much larger, rounded and hairy on the underside. They tend to hide the flowers somewhat, but putting the tree on a slope where you can walk under it makes them easier to appreciate.

We do have a couple of native American snowbells, but they’re rarely seen in gardens. Styrax americanus grows from southeastern Virginia down into the Deep South, then up the Mississippi Valley to Illinois. American Styrax grows to only about eight feet, but I’d still consider it a tree since it doesn’t have a multi-stemmed shrubby character. The typical bell-shaped flowers are quite fragrant. Sources generally report it as a bottomland species, but I’ve seen it growing on some slopes well above streams. One of the distinctive characteristics of American Snowbell is the zig-zag growth pattern of the smooth gray branches, making it easy to identify in the winter. The Bigleaf Snowbell (S. grandifolia) does indeed have larger leaves than its cousin and can grow to about twenty feet. The flowers are still about 3/4” across, but up to twenty can hang on a single raceme. It grows in wetter areas in the southeast Coastal Plain.

Given that most snowbells grow along streams, they do appreciate adequate moisture. At the same time, they don’t want permanently wet feet, so be sure they have good drainage. Although they grow as understory trees in their native habitats, full sun or part shade are also okay. Mulching the roots will keep them cooler and help to conserve moisture. As with any tree, do not mound the mulch around the base of the trunk. This can lead to bark rot or encourage little critters to gnaw through it.

So, why plant a snowbell, or their silverbell cousins, when there are plenty of dogwoods to be found? Well, I appreciate diversity—botanical or otherwise—for its own sake. It’s not that I have to have every single plant on the planet just to say I’m growing it. (Some might look at my yard and take issue with that last statement, however.) Having Species B in your garden provides some backup if some disease starts to attack Species A. I hate to pick on our native dogwoods, but they have been taking a lot of hits of late. And sometimes it’s just nice to look at a plant that’s a bit different—with white bell-shaped flowers, for instance. When planting time comes next fall, it would be worth seeking out either of the “little bell” trees.