Northwest gardeners have what fragrant, beauteous sweet peas need

Sweet peas need not be a mere June fling, an early-season flurry of fragrance and flower that dies away as summer heats up. With a few tricks and not all that much devotion, you can keep these frilly flowers in full bloom over many months. Last summer, I picked my first sweet peas at the summer solstice, and my last just before Halloween. I admit the vines were looking ratty by October but still producing the sweet-smelling, if slightly smaller, flowers that they'd been cranking out all summer long.

I figured that breeders must have unlocked the secret of heat-resistant hybrids. Not so, says Renee Shepherd, who sells some of the most irresistible sweet-pea seed around. "Heat resistance is more a marketing thing," Shepherd explained in a recent phone interview. It was sunny and warm at her display gardens in Santa Cruz County, Calif., she told me, while it was wet and cold here in Seattle. But no matter. The Northwest is ideal sweet-pea-growing country because these delicate-looking beauties adore cool weather. It's only when the vines have matured sufficiently before warm weather hits that they have the resilience to keep on blooming . . . and blooming.

Sweet peas don't deserve their high-maintenance rep. Just because they're drop-dead gorgeous doesn't mean they're difficult. Here's sweet pea 101:

• Start seeds indoors, or seed directly into the ground. Just be sure to get the plants going in the garden by the spring equinox. If you're too caught up with spring chores to get your sweet peas started, many local nurseries carry starts, but not as wide a choice of colors and kinds as available by seed.

• Provide sturdy support for the vines to climb, remembering that they might grow bigger than you expect.

• Manure is key. Dig plenty of well-rotted manure deeply into the soil before planting. Sweet peas are somehow able to suck up and transform mucky manure into sublime-smelling flowers. When my sister raised cows, her sweet peas grew so exuberantly on their diet of manure that she sold armloads of excess blooms to local flower shops. You can't overfeed these suckers; give them a couple doses of liquid fertilizer during the growing season.

• When the seedlings have a few sets of leaves, pinch them back so they branch out and grow bushy.

• Water regularly; don't let sweet peas dry out, ever. A drip system promotes luxuriant, long-blooming vines.

• Crowding invites mildew. Despite the temptation to load up your fence or arbor, thin seedlings to 5 or 6 inches apart so the mature vines will have plenty of space between them for good air circulation. Take it from someone who always plants more sweet peas than she should.

• Pick several times a week. This isn't too onerous a job, standing out in the sunshine clipping fragrant flowers to bring indoors. If you fall down on clipping them every other day or so, they'll fall down on flower production alarmingly quickly.

• Shepherd recommends any of the petite 'Cupids' to grow in pots, baskets and windowboxes. She suggests passing up the big, old-fashioned Spencer types because they're the least heat-tolerant of the bunch. "These do best in England, where they never really have much heat." Of course, that describes most of our summers lately as well.

And what kind of sweet pea does this connoisseur love most? Shepherd hesitates not a minute. " 'April in Paris' was bred to maximize fragrance," she says. "It has wavy, vanilla-colored blossoms with violet edging." She had me with the name.

Valerie Easton is a Seattle freelance writer and author of "A Pattern Garden." Her e-mail address is valeaston@comcast.net.