You say clem-atis; I say cle-mat-is.

For years, debate has raged among gardeners over how to pronounce this showy flowering vine’s name.

But there’s little debate that clematis can be a sturdy performer in Fort Wayne gardens.

With a proper choice of varieties and judicious pruning, clematis vines can bloom year after year from springtime through early fall, says Krista Baxter, manager of Neuhouser Nursery in Fort Wayne.

The important thing, she says, is that gardeners plant varieties listed as being hardy – or able to successfully overwinter – in Zone 5, which until recently was the city’s horticultural climate classification.

That’s because clematis regrows each year from the same root, which will die if exposed to overly cold temperatures, Baxter says. Many clematis varieties are hardy only up to Zone 6 or even 7, she says.

The U.S. Department of Agriculture in January reclassified most of Allen County into the warmer Zone 6a.

While most area garden centers stock only varieties that will perform locally, Baxter says: “Be very careful when you’re buying them online.”

Locally popular varieties of clematis are Jackmanii (pronounced Jack-mania), which is a purple-flowered, late-spring and summertime bloomer; and Sweet Autumn, which has smaller, more numerous white flowers and blooms through early fall, Baxter says.

Plant the two varieties near each other or so they entwine, and blooms will continue for months, she says.

New to Neuhouser this year is Josephine, a variety that has pinkish, light lavender or violet flowers and features double blooms that can grow to 5 inches across, Baxter says.

According to its developers, Josephine is a double-bloomer in another way – the vine can be pruned back after the first flush of flowers, and it will re-bloom in late summer.

Another debate about clematis is when to prune it.

“Sweet Autumn is pruned early to mid-spring, but Jackmanii, you want to prune it in early fall when everything has kind of gone dormant,” Baxter says. “Some clematis we don’t prune at all, because new growth just grows overtop of old growth.”

Pruning is done by cutting the vine back to within six inches of the soil, Baxter says. But it’s best to consult directions for individual varieties, she says.

“Sometimes you can trick ’em into coming back (by pruning), but clematis are finicky about that – you can lose the plant if it goes into too much shock – if it’s too hot or too cold or too wet or too dry,” she says.

Another finicky aspect of clematis: It likes sun for its flowers but shade for its roots, Baxter says.

And the show is splendid, Baxter says. “Clematis is a wonderful little plant.”

rsalter@jg.net