How to Grow Sweet Peas


In the Victorian language of flowers, sweet peas symbolized delicate and blissful pleasures.  How very apt for this delicate flower with a blissfully pleasurable fragrance.  Whether you intend to send someone a secret message with your bouquet, or just enjoy the color and scent as you pass by a trellis full of sweet peas, this heirloom bloom is a perfect addition to every garden.

So Many Colors to Sow!

Sweet peas are native to many parts of the world, including Peaceful Valley’s own hometown Grass Valley, California, where Lathyrus latifolius, also called the everlasting pea, sends beautiful sprawling vines across the hillsides in early summer. A perennial unscented sweet pea that is native to many parts of the U.S., it was much loved by Thomas Jefferson who cultivated it in his own garden.
Sweet Pea Closeup
The classic annual garden sweet pea, Lathyrus odoratus is originally from Italy, where local wild flowers were collected and bred for new colors, sweeter scent, stronger stalks, and other desirable traits. Many cultivars now available were bred in England, where the sweet pea has been a garden favorite for centuries.

Lathyrus odoratus is what is most commonly thought of as the sweet pea. They come in a wide range of colors, from pastels to deep shades such as pink, purple, blue, and cream.  Some are climbing vines for trellises and arbors, and some are low growing plants suitable for containers or garden borders. They all have in common a heavenly fragrance, which make them such excellent cut flowers.

Another uncommon and beautiful species of annual sweet pea is Lathyrus sativus azureus, which comes from Asia and is sometimes called the Indian Pea. It has distinctive grassy foliage with vibrant blue flowers.

Planting Your Peas

Sweet peas are a cool weather plant that should be planted early enough to allow it time to grow and bloom before the heat of summer sets in. For regions with warm winters, this means planting it in the fall after Labor Day. For regions with cold winters, plant it as soon as the ground is workable and at least a month before the last frost.
Sweet pea shoots tolerate frost, and should be planted directly outdoors. Before planting, soak the seeds overnight to improve germination. Scarify the seed by gently filing or nicking the seed coat can also help the seed to germinate.

Select an area to plant your seeds that gets full sun. If you live in an area with especially hot summers, your sweet peas will appreciate some afternoon shade. Planting low growing plants on the south side of sweet peas will help to keep the soil shaded and cool while allowing the climbing sweet pea to receive full sun on its leaves.

Plant your seeds 1” deep and 2 to 3” apart, thinning to 4 to 6” once the seedlings are a few inches tall. Seedlings should be protected from birds, slugs and snails right away, as they can quickly decimate a young patch of sweet peas.

For climbing sweet peas, install your trellis or lattice at planting time, as they will want to climb soon after sprouting. They are happy to climb on nearly every vertical support; this versatility makes them perfect for creative landscape designs.
A bee enjoys a sweet pea flower

Getting the Most Flowers

Give your sweet peas moderate water throughout the growing season. Keep down the weed competition and watch for problems such as mildew and thrips. A balanced fertilizer for flowering plants such as E.B.Stone Ultra Bloom provides necessary phosphorus and other nutrients to promote flower production.

To get the most blooms out of your plants, make lots of bouquets! Cutting flowers off the plants encourages them to make more flowers. Deadhead spent flowers as soon as the blooms begin to fade also helps to keep the plants in flower-production mode.  Pinching back the tips of branches to 2 to 3 pairs of leaves when they plants are 6” tall will encourage your sweet peas to make more flower-producing branches and give it a fuller appearance.

For the longest bloom season, select varieties that are heat tolerant. Standard sweet peas will go to seed when the summer temperatures get too high. Some varieties have been bred to better withstand the heat, giving you a longer blossom season. Royal Mix and Old Spice are good options for heat tolerant sweet peas.

For long lasting bouquets, harvest the blooms when the lowest blossom is just beginning to open. Harvesting flowers in the early morning will give you bouquets with the best scent.

Sniff, But Don’t Taste

Despite what their name may seem to suggest, sweet peas are not good to eat! The only sweet part of this pea is the honey-like scent of the flowers. In fact, sweet peas are toxic, so don’t be tempted to eat the pods when your sweet peas are finished blooming.