Sweet Pea Flowers: Planting, Care & Growing Guide

These delicate, colorful flowers are a classic addition to the garden

sweet pea flower

The Spruce / Letícia Almeida

The colorful and fragrant sweet pea (Lathyrus odoratus) is a favorite plant for informal cottage gardens and is easy to grow. It is most often seen trained up trellises or fences, but sweet peas grow beautifully in pots where it spills over the sides. They are climbing plants that bear profuse clusters of spring and early summer flowers in a wide variety of colors, including red, pink, blue, white, and lavender. Sweet pea flowers resemble fringed butterflies, while their sturdy stems appear to be folded. Plant your sweet peas in late winter or early spring. Sweet peas provide beautiful color in garden spaces, but beware because they are toxic to humans and pets.

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Learn How to Grow Fragrant Sweet Pea Flowers

sweet pea flowers
​The Spruce / Letícia Almeida 
Common Name Sweet pea, perennial pea, everlasting pea
Botanical Name Lathyrus odoratus
Family Fabaceae
Plant Type Annual, vine
Mature Size 6-8 ft. tall
Sun Exposure Full, partial
Soil Type Well-drained
Soil pH Alkaline
Bloom Time Summer, Fall
Flower Color Red, pink, blue, white, lavender
Hardiness Zones 3-8 (USDA)
Native Area Europe, Mediterranean
Toxicity Toxic to humans and pets

About Sweet Pea Flowers


Sweet pea (Lathyrus odoratus), is a climbing annual member of the legume genus. Originating in the southwest of Italy and the islands of the Mediterranean, sweet pea has been cultivated for use in gardens since the 17th century. It reached its modern form under the work of Scottish nurseryman Henry Eckford, who developed dozens of cultivars during the late 1800s.

Sweet Pea Care

Sweet peas lend a cottage feel to gardens. For many of us, fast-growing sweet peas are an instant nostalgic reminder of the beautiful, rambunctious old-fashioned gardens. These vintage varieties were selected for their vibrant colors and intense fragrance. Modern sweet pea cultivars come in almost every color except yellow, but not all of the newer sweet pea varieties are fragrant. The mature size will depend on the variety you choose to grow, but expect the vines to stretch to at least 6 to 8 feet tall. They are often grown on bamboo tripods, but typically they are grown along a trellis or fence for support.

Planting and Soil

Plant sweet pea in the late winter and early spring. Sow three seeds together about a foot between groups of seeds. Plant sweet pea seeds about 1 inch down in the soil. For better blooms, work compost into the soil about six weeks before planting the seeds. Compost will also improve poor soil.

Sweet peas prefer rich but well-drained soil. A slightly alkaline soil pH (about 7.5) is ideal.

Light

Sweet peas thrive in full sun, although in warmer climates they do well in a location that receives a bit of shade in the heat of the afternoon.

Water

Sweet peas need weekly watering, to keep the soil moist during the growing season. Check the soil by placing your finger an inch into the soil. If it's moist, there's no need to water the plant but if it's dry, it's time to give the plant a drink.

Temperature and Humidity

Because sweet peas originated in the Mediterranean, they can handle a rare chill but do best if they're planted after the last frost and in warmer temperatures in USDA zones 3-8. Sweet pea seedlings can tolerate a light frost, but the plants dislike extremely hot temperatures. Plant early to enjoy the blooms before they wither in the heat.

Fertilizer

During the growing season, apply fertilizer for sweet peas monthly. Choose a fertilizer high in potassium, such as a tomato fertilizer. Adding a bit of blood meal to the soil is thought to help keep the stems long and suitable for cutting.

Types of Sweet Peas

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

Pruning

To increase branching, which produces more flowering stems, pinch the growing tips back 1 inch when the plant reaches 4 inches tall. The more you cut the flowers, the more blooms you should get, so don't hesitate to bring some bouquets indoors. Deadhead the spent flowers to encourage continued blooming. For Lathyrus odoratus annuals, you do not need to do anything to the plant when sweet peas have finished flowering.

How to Grow Sweet Pea From Seed

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 Fahrenheit and is not too wet. In the South, you may have better luck seeding sweet peas in the fall to grow into winter.

You can get a jump start on the season by starting seed indoors, about four to five weeks before your last frost date. They will be easier to transplant if you start them in peat pots. When you are ready to transplant, pinch any flowers or buds off that may have formed, which will encourage root development. They like cool soil, so a thick layer of mulch around the plants may help sweet peas thrive.

When the plants reach about 4 inches tall in the garden, pinch the seedlings to encourage strong side shoots. Sweet pea vines have tendrils and will attach themselves to almost any type of support that has meshing or strings.

Potting and Repotting Sweet Pea

Sweet peas can also be potted into planters and placed indoors. With just a few steps, you can have a brand new sweet pea plant for your home.

You have to remove the nursery plant from its container and then brush off the excess soil from its roots. Feel free to tease the roots if they are clumped together. After most of the excess soil is shaken off, place the plant into a bigger planter and repot the soil back into it.

When you're placing the soil into the planter, be sure to press down the soil to remove air bubbles for maximum growth.

Common Pests

There are few pests or problems associated with sweet peas although aphids, mites, and pea moths are occasional pests. Slugs and snails can also eat new plants.

sweet pea flowers growing out front of a home
​The Spruce / Letícia Almeida
sweet peas 'Matucana'
Jacky Parker Photography / Getty Images
FAQ
  • Does sweet pea come back every year?

    Lathyrus odoratus is an annual sweet pea plant, very fragrant, and it does not come back every year. Lathyrus latifolius is a perennial sweet pea plant, it is not fragrant, but it will come back every year.

  • What month do sweet peas flower?

    Most sweet pea varieties will begin blooming in late spring or early summer. However, in Northern California, sweet peas may bloom later, around September and October.

  • What do sweet peas attract in the garden?

    Sweet peas work well in any garden and also in a vegetable garden, where the plant attracts bees and other necessary pollinators. They are often grown along the fence of a vegetable garden or mixed in with pole beans.

Article Sources
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Lathyrus odoratus. North Carolina State Extension

  2. Sweet Pea. ASPCA.

  3. Fragrant Sweet Peas Please the Gardener More Than the Bee. Oregon State University Extension Service.

  4. Lathyrus Latifolius. North Carolina State Extension.

  5. Lathyrus. North Carolina State Extension.