Sweet Peas - The Queen of the Annuals

Sweet Pea Flowers
Photo: gojo23


Sweet peas are climbing plants that bear clusters of flowers in a wide variety of colors including red, pink, blue, white and lavender. They are early summer flowers with a long season of bloom and they make excellent cut flowers. Sweet pea flowers resemble fringed butterflies while their stems appear folded. Luckily the stems are sturdy enough to hold up their profuse flowers.

The old-fashioned varieties were selected for their vibrant colors and intense fragrance. Many modern cultivars are on the market offering sweet peas in almost every color except yellow, but not all of the newer sweet pea varieties are fragrant.

Latin Name:

Lathyrus odoratus

Common Name:

Sweet Pea

Hardiness Zones:

Sweet peas are annuals, so they do not have a USDA hardiness zone.


They do best in full sun, although in hot weather partial shade, especially in the afternoon, will be fine.

Mature Size:

The mature size will depend on the variety you choose to grow, but expect he vines to stretch to at least 6 - 8 ft. tall.

Bloom Period:

Most sweet pea varieties will begin blooming in late spring or early summer. The more you cut the flowers, the most blooms you should get, so don't hesitate to bring some bouquets indoors.

Blooming is diminished by heat. Gardeners in hotter climates, you may have better luck seeding them in the fall, to grow into winter.

Design Suggestions:

Sweet peas lend a cottage feel to gardens. They are often grown on bamboo tripods, but they will gladly grow through shrubby plants, much like clematis. They also work well in a vegetable garden, attracting bees and other pollinators needed in the vegetable garden. They can be grown along the fence or mixed in with the pole beans.

Suggested Varieties:

There are many, many wonderful sweet pea varieties available as seed. You can find individual colors or blends. Remember that not all sweet peas are fragrant, so be sure to check the package.

  • 'Old fashioned' - Although not really a variety, Sweet peas labeled old fashioned should be very fragrant
  • Spencer cultivars - especially hardy vines with striking coloring, but not all of them are particularly fragrant
  • Bijou Group - Sweetly scented dwarf variety suitable for containers.

Growing Tips:

Soil: A well-draining soil rich in organic matter, with a soil pH that is slightly alkaline at about 7.5 is ideal for sweet peas.

Planting: Sweet peas are usually direct sown. To assist germination, seeds should be scarified, by nicking and/or soaking in water for several hours, to soften the seed coating. Seed can be started outdoors, as soon as the ground has warmed to about 50 degrees F. and is not too wet.

You can get a jump start on the season by starting seed indoors, about 4 - 5 weeks before your last frost date. They will be easier to transplant if you start them in peat. When you are ready to transplant, pinch off any flowers or buds that may have formed, to encourage root development.

When the plants reach about 3-6 in. tall, pinch the seedlings to encourage strong side shoots.

Sweet pea vines have tendrils and will attach themselves to most any type of support that has meshing or strings. Regular deadheading or better still, cutting for display, will keep them blooming longer.


Sweet peas require regular watering, especially as the temperature increases. They prefer a somewhat rich soil and can be fed monthly with a fertilizer high in potassium, as used for tomatoes. Adding a bit of blood meal to the soil is thought to help keep the stems long and suitable for cutting.

Pests and Problems:

There are few pests or problems associated with sweet peas, however groundhogs and rabbits will eat the seedlings, so I would recommend some protection when they are first in the ground.

I use a spray repellent. Other than four-footed pests, they are usually done in by the heat.