You needn’t be a botanist nor even a studied gardener to know a hydrangea when you see it. The large, rounded flower-heads and straight stems of bigleaf hydrangea (H. macrophylla) cultivars are instantly recognizable, and the confusion over when to prune them and what makes the blossoms blue or pink has seemed to add intrigue, rather than deter interest. Meanwhile the reliable, fail-proof conical blooms of panicle hydrangea (H. paniculata) make it a go-to among summer-blooming shrubs, and cultivars in a wide range of sizes have added to its applicability.
These two Asian species have long been well represented in yards, gardens and public landscapes, but a North American cousin is steadily gaining ground, thanks to a slate of cultivars that play up its natural appeal. Make way for smooth hydrangea (H. arborescens).
THE SPECIES
can be found growing wild amid woods, slopes and stream banks throughout the Mid-Atlantic and Southeast states. It’s a deciduous shrub with rounded,. (Its foliage is noticeably thinner than the bigleaf’s, though.) The species grows three to five feet tall and at least as wide; it can spread by suckers to fill in available space. It blooms greenish white in summer. Its infloresences are of the lacecap type—a dense, flat cluster of tiny but numerous fertile flowers ringed by a scattering of showier sterile flowers.
