Herbs in the Landscape
Sweet Pea (Lathyrus odoratus)
The sweet pea is a charming, old-fashioned flower that excels in cottage, border, woodland, and cutting gardens as well as in containers to create a vintage look. From about May to July in St. Louis, the flowers appear in clusters reminiscent of butterfly wings and have a honey-orange scent. They are delightful in multiple shades of color that include blue, pink, purple, magenta, red, white, orange, and bicolors. They usually are pastel, though can be rich and bright.
A Sicilian monk introduced sweet peas to England in 1699. Sweet peas became very popular in North America. By the late 1800s, Burpee and other California growers shipped train loads of seed across the United States for use in gardens and to grow for flower arrangements. Many heirloom varieties are still available.
Sweet peas are annual plants and can climb to 6-9 feet and grow about 2-3 feet wide in just one season. They will need support and grow well on trellises. There also are bush varieties available. Not all sweet peas are sweet-smelling, although heirloom climbing (not bush) varieties are often fragrant. Sweet peas do best when sowed in the late winter or early spring. Planting indoors about 6-8 weeks before the last frost date works well. In the St. Louis area, that is mid-February to early March. They can be transplanted outside when the soil is ready to work, before the last frost. They can withstand some frost. It is suggested to cultivate compost about four inches deep into the soil before planting. They prefer full-sun and well-drained, slightly alkaline soil. Mulching will keep the roots cool. Adding fertilizer high in phosphorus encourages blooming. They bloom prolifically. Cutting their flowers encourages even more blossoms. In the St. Louis area, they will succumb to hot weather. There are no serious pest or disease problems, although slugs and snails may harm young plants. Sweet peas are toxic, and they should not be planted near edible sweet peas. Although they do not have medicinal or culinary uses, they excel with their beauty. They also attract bees and other pollinators.
The poet John Keats wrote about sweet peas in adoring terms. It is said that it is impossible to speak ill of someone when sweet peas are in the room. Sweet peas look lovely in floral bouquets. In France, sweet peas are given to brides for good luck. Calling someone “Sweet Pea” is a term of endearment, like “Sweetheart.” In the language of flowers, sweet pea symbolizes blissful pleasure, friendship, and gratitude for a lovely time.
