Secrets to Sweet Pea Success



An exquisite fragrance, ruffled blossoms, and a palette of glowing colors (not just pastels!) make sweet peas the most irresistible and memorable of garden flowers. A small bouquet of the fluted beauties perfumes a room with a scent that reminds me of orange blossoms and honey. Sweet peas' soft, seductive fragrance never overpowers or cloys, and isn't replicated in any artificial perfume.

I realize that sweet peas have a reputation for being difficult to grow, particularly in the Midwest and Southeast. But after talking to gardeners all over the country, I am convinced that sweet peas can be grown successfully almost anywhere, and in those few areas where they are more challenging, their beauty and fragrance are well worth the effort. Give them the proper conditions, plant them at the right time for your climate, and you will be rewarded with a delight for your senses that gardeners have treasured for centuries.
Timing Is Key

The first step in growing sweet peas successfully is determining the best time to plant them. We generally think of them as spring flowers, but early spring may not be the optimal planting time in your climate.

In mild-winter areas, where summers are hot but the ground does not freeze in winter, sow sweet-pea seeds at the same time you plant bulbs such as daffodils: roughly from October through early November, or as soon as the weather starts to cool but rains haven't started. This is what we do where I live in Northern California.

In these conditions, the seeds germinate and develop strong root systems but won't show much topgrowth. In early spring, longer day length brings on rapid growth and the vines shoot up.

Organic grower Judy Barrett, from Austin, Texas, who publishes the magazine Homegrown, advises that if winters are dry in your area, you shouldn't forget to water your sweet-pea seedlings. In very hot areas of Texas and Florida, plant sweet peas where they will get afternoon shade.

If you miss the chance to plant the seeds in fall, you can also plant sweet peas in late winter--January or February--where summers get very hot (as in southern California or much of Texas).

In mild-winter areas that have long wet winters with cool summers, like the Pacific Northwest, sow the seeds in April or May, says Seattle gardener Susan Shecket. She cuts "armfuls of blooms" from July through September.

Where winters are moderate, such as the mid-Atlantic states, with humid summers and early, unpredictable heat, plant seeds very, very early--as soon as the ground is workable--in rich, well-drained soil. Don't wait until your last-frost date (sweet peas can tolerate light frosts), and plant much earlier than other annual flowers such as sunflowers or cosmos. Your sweet-pea plants won't be mature enough to handle early high summer temperatures. Be sure to water your sweet peas when it doesn't rain--they need regular moisture.

To get an early start and also deal with unpredictable spring weather, Nancy Hanmer, a market gardener in New Oxford, Pennsylvania, starts seeds indoors in jumbo packs or 4-inch pots in late March to plant out as soon as they have two or three pairs of leaves. She also sows seeds directly in the soil in early to mid-April. Whether cold and rainy weather lasts well into spring or hot weather hits suddenly, she's prepared with strong seedlings.

In frigid-winter climates, where the ground freezes hard and heaves, as in New England, wait to plant until the spring soil can be easily worked, usually in late April through mid-May, say Susan Keating, owner of Sweet Pea Gardens in Surry, Maine, and Jay Leshinsky, who manages the student gardens at Middlebury College in Vermont. They also get a head start by sowing seeds indoors four to six weeks early, to plant out as soon as possible when weather permits, all the way through May. No matter which of these strategies you try, remember that late mild frosts do not hamper sweet peas. In the far north, sweet peas planted out in April and May reach full bloom in late summer and continue almost until the first frost. If you have very hot summers, too, plant where the vines will get afternoon shade. And remember to keep your sweet-pea patch moist.
Planting and Care

Choose the location. Sweet peas grow best in full sun with very well drained, rich soil and reliable air circulation to prevent mildew. (Exception: Give sweet peas a little afternoon shade where summers are broiling.) If your soil is heavy clay, work organic material into the spot for better drainage. Where the soil is very soggy, plant sweet peas in raised beds.

Sow seed. Spacing your sweet-pea vines properly protects them from diseases, so follow seed-packet instructions and allow a bit wider spacing if you live in a humid climate. Sow seeds 1 inch deep and 2 to 3 inches apart. Sweet-pea seeds germinate in 10 to 28 days, depending on weather and soil temperature. If your sweet peas do not germinate well, dig down to see if the seeds are still there. If they have rotted or disappeared, plant more right away, as they will catch up quickly. You can expect 75 to 85 percent of sweet-pea seeds to germinate. A small percentage always stay dormant, allowing Mother Nature a safety zone in the wild if weather conditions are poor. To leave out the dormant seeds, soak the seeds overnight (no longer) in tap water and plant only those that have swelled.

For the very best germination rates, do not soak, but nick the seeds to allow moisture to enter the seed coat. To do this, use nail clippers to simply make a small slice in the outside seed coating. No need to gouge out a piece; just allow an opening for moisture to enter naturally. This nicking process takes extra time but guarantees great germination.

Seedling care. When seedlings reach several inches tall, thin them to stand about 5 to 6 inches apart, allowing the vines room to grow and mature. When seedlings have three or four sets of leaves, pinch off the top set to encourage branching out. Protect the seedlings from slugs and snails, using an abrasive barrier like diatomaceous earth or a nontoxic slug bait like Sluggo. If seed- and seedling-eating birds typically plunder your garden, suspend netting over seedlings until they are 4 to 5 inches tall.

Water regularly. I can't stress it enough: Adequate water is critical to success with sweet peas. Be sure to water germinating seeds, seedlings, and actively growing mature vines regularly when rain does not keep them consistently moist. Push your finger into the soil bed up to the first knuckle, and if it's dry, water the sweet peas. Mulching is also important. I like to use an inch or two of well-composted horse manure, which is readily available here; composted leaves are another good choice.

Fertilize twice. Sweet peas are heavy feeders, so before you plant, amend the soil well with lots of rich compost or well-rotted manure. During the growing season, fertilize at least twice by drenching the soil with a liquid fertilizer made from a tablespoon each of fish emulsion and liquid kelp diluted in a gallon of water. (If your sweet peas are growing in containers, fertilize them every two weeks.)

Thwart insects. Sweet peas are susceptible to aphids. Wash them off with blasts of water. You can effectively control thrips, an occasional problem, with sticky pheromone traps interspersed among the vines to attract and trap them. Constant air circulation and avoiding watering late in the day and evening helps prevent mildew (until the plants succumb to it naturally at the end of their bloom period).

Provide support. All the tall vining varieties climb naturally on just about any vertical support system. They grow up strings, netting, wire or wooden fencing, or almost any kind of trellis. (In very hot areas like Texas, avoid wire fencing--it can conduct heat and burn the tender vines.) You can also use tall branches left over from tree pruning driven into the soil. Since the tendrils cannot twine around thick poles like bamboo, wrap twine or netting around them so tendrils can grip. Anchor the supports well and put them in place either before you plant the seeds or when seedlings are a few inches tall.

Pick, pick, pick. The most effective and satisfying way to make the season of glorious bloom last is to pick bouquets early and often. The more you pick, the more flowers you get and the longer plants continue blooming before they go to seed. Cut sweet peas when the lowest blossom on each stem is just beginning to open. As the season progresses, the stems become shorter but the flowers are still full-size and lovely.

Visit for a sweet-pea growing guide and more on flowers for cutting gardens.
Sweet Peas in Containers

Have a small garden or just a patio? You can grow short, mounding varieties of sweet peas like 'Color Palette Cupid' in containers. The vines grow 8 to 10 inches long, with sweetly scented flowers on softly cascading branches. Colors are a mix of rose, lavender, pink, dark purple, and mahogany.

1. Plant seeds directly in deep containers at least 8 inches in diameter or rectangular window boxes at least 6 inches deep. Fill planting containers with premoistened, fresh potting soil before planting the seeds 1 inch deep and 3 inches apart.
2. Place the container in full sun. When seedlings are 2 inches tall, thin them to 4 inches apart. For example, you would have four or five evenly spaced plants in a 12-inch-diameter container. This gives plants room to grow and spread as they mature.
3. Don't allow the sweet peas to dry out.
4. Fertilize them every two weeks with fish-and-seaweed-based liquid fertilizer.
5. For longest bloom, remove faded blossoms regularly.

Select Sweet Peas

The annual species Lathyrus odoratus is the familiar garden sweet pea. You can choose from dozens of varieties in a wide range of colors, from the most delicate pastels to rich, vivid deep hues, including stripes and bicolors. Varieties range from 8 inches to 10 feet tall, so you are sure to find one or more that suit your landscape.

Tall, vining varieties. These vigorous climbers reach 5 to 10 feet tall with many stems of blossoms over a six- to eight-week bloom period. Three of the most popular flower forms:

Old-fashioned or heirloom grandifloras. Dating from the late 19th century, grandifloras have small-petaled, dainty flowers in a wide variety of named shades and bicolors. Commonly available varieties include 'America' and 'Painted Lady'. Mixes include 'Perfume Delight', 'Old Spice', 'Queen of the Night', and 'Jewels of Albion'. They are all very fragrant.

The tall Spencer types, with larger, waved, and ruffled elegant blossoms, are widely popular in England and available in more limited quantities in North America. Some Spencers are very fragrant; others just mildly so.

American varieties bred in the mid to late 20th century with good-size flowers, moderate scent, and wide availability include the Mammoth and Royal Series.

Early bloomers. The Elegance Series, developed for the cut-flower market, are the earliest-blooming sweet peas available, often showing color at least several weeks before other varieties. Most Elegance sweet peas, however, are not particularly fragrant. Varieties in this series that are commonly available to home gardeners include 'Winter Elegance', 'Chiffon Elegance', and 'Velvet Elegance'.

Container and window-box varieties. These diminutive plants, with 8- to 10-inch stems or mounding and spreading habits, need no supports and look lovely in pots. I recommend 'Little Sweetheart' and the bicolor Cupid Series heirlooms. Try the mix 'Color palette Cupid'.

Nonclimbing dwarfs. Short sweet peas, some without tendrils, do not need vertical supports. Look for 'Explorer', 'Patio', and 'Super Snoop'.

Baker Creek Heirloom Seeds, Mansfield, MO; 417-924-8197,

Renee's Garden Seeds, Felton, CA; 888-880-7728,

Select Seeds, Union CT; 800-684-0395,

Sweet Pea Gardens, Surry, ME; 207-667-6751,
newbie hint

When seedlings have three or four sets of leaves, pinch off the top set to encourage branching out of more flower stems.
master's tip

To maximize germination, nick sweet-pea seeds with a nail clipper before planting to allow moisture to get inside the hard seed coat.

PHOTO (COLOR): Cutting sweet peas for bouquets encourages the vines to keep producing more blossoms. Sue Keating (left) of Sweet Pea Gardens in Maine, where this article's photographs were taken, plants In late spring for late summer bloom.

PHOTO (COLOR): Clockwise from top left: the heirloom 'Garden Orchids'; tall vining sweet peas grow on wire trellises; Spencer types have very large blossoms; long-stemmed 'Cheri Amour' Is perfect for cutting; the ruffled, pastel swirls of 'Saltwater Taffy'.

PHOTO (COLOR): When summer heats up, mulch Your sweet-pea containers and move them into afternoon shade.

PHOTO (COLOR): Aphids in Paris: the Intensely fragrant 'April In Paris' (left), with aphids feeding on a blossom; lady beetles eliminate the aphid problem (center); at Maine's Sweet Pea Gardens (bottom), Haggle and a friend admire the colorful bouquets.

PHOTO (COLOR): 'Cupani' (below) is fragrant and heat-tolerant. Ample spacing between sweet-pea vines (bottom) keeps them beautiful and disease-free.


Written by Renee Shepherd; Photographs by Stacey Cramp

Renee Shepherd, owner of Renee's Garden (which specializes in sweet peas), writes frequently for gardening magazines and lectures widely. She is finishing her third cookbook. She fives in Northern California.

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