great shrub: physocarpus opulifolius
I T’S THE ONE EVERYONE ASKS ABOUT whenever I have tours; the one that everyone thinks is a Viburnum but isn’t. Physocarpus opulifolius ‘Diablo,’ the maroon-leaved form of ninebark, is a great shrub: easy and showy over a long season, a giant fountain-shaped creature that attracts attention even from a distance. But it’s not the only variety I grow…there are others. Physocarpus opulifolius: Second in a series on great shrubs.
Physocarpus are called ninebark because of their exfoliating bark, a trait that’s listed as an ornamental feature in catalogs and reference books, but frankly I say hmmmm….at least to that part of the good p.r. around these plants the last few years. Yes, the bark peels, but ninebarks can be a bit rangy so don’t expect the textural and sculptural winter beauty of a Stewartia or Kousa dogwood or lacebark pine (Pinus bungeana). I wouldn’t put this right by my door in the place of 365-day honor, much as I love the plant, a native (in its plain green form) of the eastern United States.
Long before I grew ‘Diablo,’ I brought a rooted cutting of the golden-leaf form of Physocarpus (above), called ‘Dart’s Gold,’ home from Western Hills Nursery in Northern California. Or at least I thought it was ‘Dart’s Gold.’
But like ‘Diablo,’ my so-called ‘Dart’s Gold’ got really big in time, like 10 by 10 feet or even wider; the labels say otherwise, that it gets to just 5 feet or so. I suspect my gold one is just ‘Luteus,’ or maybe ‘Luteus’ and ‘Dart’s Gold’ are the same thing, who knows? (Don’t plant names drive you crazy?)
Each of these fast growers can get cut down hard if they outgrow their space and will resprout from the base vigorously, or the tactic can just used every couple of years to prevent them ever reaching full size. Hard prunings are best accomplished in very early spring, but every year it’s best to take out some of the oldest stems at the base to make room for more fresh ones.
My ‘Dart’s Gold’ is in its third total, to-the-ground resurrection, with Round 4 coming next April or thereabouts; my oldest of several ‘Diablo’ has seen itself beheaded once so far. But a full-grown ninebark is a handsome thing, from May to late October here.
If a smaller plant is what you are after, an even more recent introduction called ‘Summer Wine’ (maroon leaves, like a half-sized ‘Diablo’) or even ‘Coppertina’ (copper foliage, above) would make a good choice.
All are hardy in Zones 3-8, but the hotter it gets where you are the more the leaves may fade from their peak color toward greener in high summer. All are also loved by deer (but as you may recall, I have a deer fence, which keeps deer from gnawing on the shrubs in the big borders like the one below, where ‘Diablo’ is at near left). No plant is perfect, you know.