Originally published Jan. 23, 2005
By Valerie Easton, former Natural Gardener writer
FOR FILLING UP garden space quickly with style and diversity, look to giant perennials. Whether you’re beginning a new garden, renovating an old one or simply trying to fill a patch of bare dirt, you can have architectural scale and showy blooms next year, if not this one, by selecting perennials that grow large. When planted lavishly, these showboats gratify with the effect of a near-instant garden.
A caution: Anything so luxuriant will of course outgrow its bounds, no doubt sooner than you intend. Perennials never spread to a certain point, then stop just where you’d like them to. Nature in its abundant vigor isn’t like that. So be prepared to give over plenty of space to these racehorses of the garden, or keep your spade and clippers handy to make sure they stay under control. All you need to do is harden your heart a bit and yank them out once more tidily growing shrubs have filled in.
Some famous gardening friends of mine, master showmen themselves, like to fill narrow borders with oversized plants so their lucky visitors feel submerged in flower and leaf, not unlike Alice in Wonderland after she sipped the shrinking potion. It’s just fun to have plants blooming over your head, and heady for the gardener to create such a scene in only a season or two.
It is said of perennials that first they sleep, then they creep, then they leap. But most of the plants listed below take far fewer than three years to show their stuff. Prepare the soil with generous additions of compost, top-dress with a little well-composted manure, water until established and stand back.
• Euphorbia characias subsp. wulfenii prefers a dry, sunny spot in the garden, where it’ll send up tall stems crowded with blue-green leaves topped off in late winter by domed heads of chartreuse bracts. It soon spreads into an imposing clump at least 4 feet high and so handsome you’ll be pleased the foliage persists throughout the year.
• Gunnera manicata is the granddaddy of huge perennials, with dinosaur-snack-size leaves growing on fat, hairy stalks that emerge out of the ground like a seismic upheaval. The rounded, lobed leaves are thick with prominent veins and spread an impressive 5 feet wide when grown in the rich, damp soil this mammoth prefers.
• Ferula communis, or giant fennel, is an airily statuesque beauty that grows 10 feet high. Its lacelike, golden cow-parsleyesque blooms are a party of a plant with great presence in the garden. It likes sun and well-drained soil, but is happy to grow most anywhere.
• Inula magnifica is the tallest daisylike flower you can imagine, growing into a tower topped with fluffy yellow midsummer blooms. The leaves are long, rough and hairy, and despite its height of 6 to 8 feet, the plant doesn’t need staking.
• Macleaya cordata, or plume poppy, can be a spreader, but volunteers are easily pulled out. Grown mainly for its distinctive foliage rather than its creamy white clouds of little flowers, plume poppies are great back-of-the border plants. The leaves are large and deeply lobed with pale, felty undersides.
• Lobelia tupa grows 8 feet high, and in late summer sports large, tubular flowers in hot-cha-cha red.
• Melianthus major, or South African honey bush, has some of the prettiest foliage on the planet. Strong stems grow 8 feet high and support luscious leaves so deeply toothed as to appear almost pleated, in an exotic shade of blue-green-gray.
• Crambe cordifolia is the David Copperfield of the plant world. You can’t believe that a huge puff of starry white baby’s-breath flowers could emerge from the thick clump of rough leaves to hover in a cloud of starry bloom 6 feet in the air for weeks in midsummer.
• Cephalaria gigantea might need to be staked, but it’s worth it, because the 8-foot stems are topped off with pale yellow pincushion flowers floating high in the sky.
Then there are cardoons, Joe Pye weed, foxgloves, echinops, giant rhubarb, verbascums …
Now In Bloom
For sweetly delicious winter perfume, nothing beats Daphne mezereum. Native to Great Britain, this daphne is an upright deciduous shrub that grows to about 6 feet high. Long before the leaves appear, its stiff twigs are coated in long-lasting, starry pink and purplish-red flowers. D. mezereum ‘Bowles’s Variety’ has white flowers followed by yellow berries, while the pink-blooming forms have showy red berries in summertime.