Growing Sweet Peas in Winter, Spring and Summer

By Bob Chapman

For many gardeners few flowers are as evocative as sweet peas. Their delightful fragrance, the wide range of pastel colors, the ease of growing them and the prolific amount of blooms make these flowers one of the top ten on most gardeners lists of favorites. There are varieties that bloom in winter in mild winter areas, in early spring and in summer. In addition to the well-known "telephone pole" sweet peas there are many varieties of knee-high or bush sweet peas suitable for growing in containers. Here are a few tricks about successfully growing these garden favorites.

SELECTING THE VARIETIES OF SWEET PEAS
 Purchase seeds (or transplants) that will bloom in the time frame preferred.
 'Early Flowering Multiflora' or 'Early Multiflora' (formerly called Early Spencers) are the varieties to plant in early fall in mild winter areas. They will bloom in winter when the days are shorter
 Spring flowering types are planted in the fall and early winter. Look for 'Spring-Flowering Heat-Resistant Cuthbertson Type', 'Cuthbertson's Floribunda' or the 'Floribunda-Zyolanck' strain.
 Summer-flowering sweet peas are those varieties that require at least 15 hours of sunshine to grow and bloom properly. Plant these varieties in the spring when the soil warms up. 'Galaxy' and 'Plenti-flora' are the two most commonly found.
 The so-called bush-type (or knee-high) sweet peas have strong vines but have pre-determined growth heights. These types stop their growth at 8 inches on up to 3 feet, depending on the variety. Some may need support, while others will do just fine with no help needed. These varieties make excellent container plants.
 Bush-type sweet peas are planted for early- or spring-flowers. They do not do well in the summertime. Here are some common varieties: 'Bijou' grows to about one foot in height. They are self-supporting. 'Cupid' grows to just 4-6 inches high and will trail on the ground. 'Knee-Hi', an old time favorite, will grow to 2 1/2 feet with larger flowers five or six to a stem. 'Little Sweethearts' reach about 8 inches in height and need no support. 'Snoopea' will grow to 12-15 inches high and is self-supporting. 'Supersnoop' grows to two feet high and needing no supports. 'Jet Set' sweet peas are very bushy, growing to 2-3 feet tall and they do need support.

PREPARING THE SEEDBED AND PLANTING THE SEED
 Dig a trench about a foot deep.
 Then mix in generous amounts of organic matter (compost, mushroom compost or nitrogenized redwood sawdust) to the soil removed from the trench.
 Backfill the trench about six inches deep, leaving some of the soil/organic matter mixture out on the side of the trench.
 To hasten germination, soak the seeds overnight.
 Plant the seed about an inch deep and two inches apart in the bottom of the 6-inch-deep trench.
 When the seedlings are about 5 inches high, thin to 6 inches apart and carefully backfill around them, using the soil/organic mix. Leave the topmost leaves showing. Pinch the tops to encourage branching.
 When growing sweet peas in containers use OSH Potting Mix, a special formula used by commercial growers.
 Digging a trench is not necessary to grow the bush-type sweet peas, but do mix in generous amounts of organic matter into the soil before planting

TIPS FOR PROPER CARE AFTER SOWING THE SEEDS

 Water generously, never letting the soil dry out. Be aware that newly planted seeds may rot if the soil is too wet for too long.
 Place supports for the taller-growing sweet peas. These include trellises, strings, poles, or more conveniently, bird netting for the vines to climb. Place the supports so that the bottom portion is close to the ground. This provides a place for the tendrils to grasp and keeps the young vines from falling over.
  Prevent birds, slugs and snails from eating the seeds or young plants. Use bird netting over the trench and use Sluggo, an effective and safe snail bait which can be used around pets or Bug-geta, an effective bait, but should not be used if you have pets.
 Spray for powdery mildew at the first sign of this insidious disease. Look for a grayish film on the leaves. It's hard to spot, but a close watch will reveal the disease.
 To prolong the blooming period, cut the flowers every other day. Remove all seedpods, as they will inhibit the future formation of flowers.
 Fertilize the vines every month with a complete fertilizer, such as Superfine All-Purpose Food.

Follow the suggestions above and you can enjoy the fragrant and colorful blooms of sweet peas nearly all year in mild winter climates.

Bob Chapman is a well-known professional gardener and landscape contractor. Currently retired, Bob now spends his time contributing many free-lance garden articles and columns, and is a much sought after lecturer and horticultural consultant.

Since 1987, Bob has appeared as a regular columnist for the San Jose Mercury News. Besides the Mercury, his writings have appeared in the San Diego Tribune, Sacramento Bee, Fresno Bee and the Times Newspaper Group. He is the 1991 winner of the Quill and Trowel Award of the Garden Writers Association of America for the best newspaper gardening article in North America.

Bob majored in Ornamental Horticulture at Cal-Poly, San Luis Obispo. He also served as a member of the Professional Gardeners Association.