As the executive director of the American Rhododendron Society, Laura Grant knows a thing or two about these misunderstood shrubs.
I was surprised to learn for example, that her rhododendrons go through the winter without the aid of burlap wraps or anti-desiccant sprays. “If you site the plants carefully, it's unnecessary,” she explains. “Rhododendrons are hardier than most people think provided they have good drainage at root level-in fact that's true of most plants. The trick with rhodos is to plant them so they're protected from noontime winter sun and strong northwest winds, and that's where the conifers come in.”
“Rhodos are shallowly rooted plants, and it's essential that the roots of container-grown specimens are carefully spread out into the surrounding soil when they're installed,” says Laura. She always recommends that rhodos be grown in raised beds, and this is particularly critical in clay soils.
“Rhodos look best when planted in groups, so amend the planting area with lots of humus and organic matter. If your soil is very alkaline, then adding elemental garden sulfur at the base of the raised beds is advisable,” she says.
For gardeners living in Zone 6 or warmer, Laura suggests ‘Janet Blair', a variety that “almost anyone should do well with-it's probably the best all-rounder.” Growing two metres wide by two metres high, it has lovely pink flowers and is very healthy and floriferous.
Her own favourite is ‘Herbert' azalea (Zone 6), one of the Gable Hybrids that sport vivid purple, hose-in-hose flowers and tolerate a wide variety of soil types. Generally recognized to be the hardiest of all rhodos is the Northern Lights Group (Zone 3), but, Laura says, “If you're still unsure, then go to www.rhododendron.org; they can advise you on the best bets in your region.”