Learn how to grow sweet peas including information on fragrant and unusual varieties.
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Lathyrus odoratus
Other Name
annual sweet pea
Sun Requirements
full sun, part sun
Bloom Period and Seasonal Color
mid summer to fall to colors such as white, purple, pink, red, and bi-colors
Mature Height x Spread
2 to 8 feet x 1 to 2 feet
Added Benefits
attracts beneficials, deer resistant
This annual vine grows and flowers best during cool weather so is particularly attractive in coastal and northern parts of New England. It adds a touch of elegance and, depending on the variety, fragrance, to any garden bed or container. Heirloom varieties tend to be the most fragrant, while modern varieties have a wider variety of plant sizes. This vine is a great cut flower for arranging and bringing the scents of summer indoors. There’s nothing more enticing than a vase full of fragrant sweet pea blossoms. It need support to grow, but the tendrils are strong so sweet pea vines will cling to many objects such as fences, thin poles, netting and wire.
Where, When and How to Plant
Sweet peas are best sown in a full to part sun location directly in the ground on well-drained, compost amended soil in spring. Plant climbing sweet peas along a fence, trellis or wire. Bush varieties can be planted in containers. Nick the seeds wit h a nail file and soak them overnight in warm water to hasten germination. Plant once your ground has dried out, spacing the seeds 6 inches apart. In cold areas of our region, to get an earlier flowering crop, consider starting sweet pea seeds indoors in pots 4 to 6 weeks before your last frost date.
Growing Tips
Since sweet peas are a legume, they need little additional fertilizer. They do grow best on a neutral pH soil, so add some lime if your soil is acidic Keep the soil evenly moist for good germination and growth.
Regional Advice and Care
Sweet peas may dry up and die in mid summer in warmer parts of New England. Enjoy the early summer crop and consider planting a crop in mid summer for fall. Deadhead spent flowers to encourage more blooms. Avoid planting in the same location each year since diseases can build up in the soil to attack the sweet pea plants. They also sometimes get powdery mildew disease. Space vines further apart to increase air circulation to avoid this fungal disease. Unlike garden peas, sweet peas are poisonous and can’t be eaten.
Companion Planting and Design
Grow tall varieties along a fence, lattice, up a lamppost or thin pole, on a teepee or in a cutting garden. Plant bush varieties in containers or window boxes. Plant fragrant varieties close to the house or windows where they can be enjoyed. This traditional English garden plant pairs well with peonies and roses. They also can grow up the stalk of tall flowers, such as sunflowers, adding color before the sunflowers bloom.
Try These
‘Old Spice’ and ‘Mammoth Mix’ are fragrant heirloom varieties that come in many pastel colors. They are particularly heat resistant. ‘Incense Mix’ is a 6 foot tall mix of colors that has long stems making them great for cutting. ‘Villa Roma Mix’ is a dwarf variety that only grows 14 inches tall.
Excerpted from my book, New England Getting Started Garden Guide.
Podcast Transcript
Sweet peas are known as the Queen of the Annuals. And why not, these climbers have vivid colored flowers that look like floating butterflies, a long season of bloom in our climate, and an amazing scent. The sensuous fragrance is a captivating blend of honey and orange with varying layers of subtlety. It invokes love, romance and passion. But I get carried away.
Unlike garden peas, sweet peas are relatively new on the garden scene. They were first discovered in Sicily in the 1600’s by a Franciscan monk name Cupani. In fact, you can still buy this original ‘Cupani’ variety to grow in your garden.
But there are many other varieties to grow. Some are tall and need trellising, while others, such as ‘Windowbox Cupid’, can grow in small containers. I like the fragrant varieties. Try ‘Old Spice Mix’ , ‘April in Paris’ and ‘Perfume Delight’ for some knock your socks off smells. But don’t get discouraged if your sweet peas aren’t very fragrant even with these varieties. Sweet peas need sunny days and cool temperatures to smell their best.
Sow sweet peas seeds once the ground can be worked and all danger of a hard freeze has passed. You can also sow them indoors one month before planting and then transplant seedlings into the garden. Nick the seed with a nail file and soak them in warm water overnight to hasten germination. Plant them near a window or door to enjoy the scent. Support tall varieties with a trellis or fence and in 50 days you’ll be snipping fresh pea blossoms for indoor bouquets. But don’t be tempted to eat them. The flowers and pods are poisonous.
