A Beginner’s Guide to Growing Sweet Peas

Sweet Peas (properly called Lathyrus odoratus) are one of the great plants for cutting, and they provide irresistible colors and fragrance for spring and early summer bouquets. The delicate flowers are available in a wide range of rich colors, and they scent the air with grapelike perfume. To help those who have never grown Sweet Peas in a garden or a container pot, we asked our nursery manager, Barb Pierson, to offer a bit of advice. Her tips will help any novice or green thumb enjoy a bountiful crop of these beautiful flowers.

Why do people grow Sweet Peas?

Sweet Peas are grown for their beautiful ruffled flowers in shades of pastels, blues, and bi-colors. Many varieties are fragrant making them a desirable cut flower. Sweet Peas have a long history of cultivation and breeding for both the home gardener and the florist trade.

Sweet Pea ‘Zinfandel’

How do I go about growing Sweet Peas?

Sweet Peas can be grown from seed and sown directly in the ground after a seed treatment or, more easily, from a started plant. Here at White Flower Farm, we sow 3 seeds per pot to produce 3 growing Sweet Pea vines.

Where do I plant them and when?

Sweet Peas enjoy full sun in the northern half of the US. In the South, they can benefit from afternoon shade. They like cool roots and cool temperatures so they are planted as early as possible in the spring. A light frost will not harm newly planted seedlings. In very warm areas, they can be planted in the fall and grown through the winter and early spring. For best results, add compost to the soil and check that the area is well drained. Raised beds can be a good way to grow Sweet Peas.

Sweet Pea ‘Cherie Amour’

Do they need any special care while they are growing?

Because Sweet Peas are vining, they need support to grow up and flower. Many types of structures can work such as a trellis, supports with mesh or twine, or fences. They need a structure that is well anchored in the ground to support the weight of the vines. The plants will form tendrils that wrap around the support you provide.

They like a nutrient-rich soil so adding compost at the time of planting is recommended, and mulching Sweet Peas will keep the roots cool and retain moisture while growing.

Once the plants have grown to about 6” in height, it helps to pinch the growing tips by 1”, which will help the plants branch out and produce more flowering stems.

Sweet Pea ‘Cupani’s Original’

What are the most common mistakes that people make with Sweet Peas?

  • Waiting until mid-summer to plant them – they don’t like the heat and won’t produce flowers as readily
  • Not providing support at the time of planting. It is difficult to add your trellis or support after the plants have started growing
  • Poor soil without adding compost or fertilizer will result in weak plants and fewer flowers
  • Planting Sweet Peas too close together without thinning them can create an environment for powdery mildew and crowding, which reduces flower count

Do Sweet Peas produce pods that you can eat like the ones you find in the grocery store?

Although the seed pods look like Snap Pea pods, they are not edible. You can save the pods and seeds to produce plants for the following year. Keep in mind that the seeds may not produce plants that are the same color as the parent plant.

Will the plants come back again next year?

In most climates, the plants are not hardy through the winter. Even in warm climates, they are re-planted with fresh seed and plants to produce the most flowers and have vigorous growth.

When do they bloom? Are there tips for getting extra blossoms?

Sweet Peas will start blooming approximately 4 -6 weeks after visible vining. Timing of bloom will depend on whether the plants have been pinched back. Pinching may slow growth somewhat, but it will produce bushy plants with more flowers. Sweet Peas will grow and flower faster as the days get longer in spring and early summer. Using compost or dried aged manure will help provide nutrients to produce large abundant flowers. A fertilizer with higher phosphorus than nitrogen can boost flower production as well.

Sweet Pea ‘Cherie Amour’

What is the process for cutting the blooms?

Cut the blooms in the morning before the sun has had time to dehydrate them. Choose freshly opened flowers on the longest stems for your vase. Do not cut the main stem of the plant, just the side flowering stems.

Why should I get my Sweet Peas from White Flower Farm?

Our plants are produced in our greenhouses in spring and are shipped to you at the proper time for planting in your area; no seed treatment or waiting for germination required. We ship our Sweet Peas in 4” pots – each containing 3 fully rooted seedlings – and they arrive ready to go into the ground. This saves you the time and trouble it takes to grow Sweet Peas from seed. Buying and planting our Sweet Pea seedlings is the quickest way to enjoy these fragrant flowers outdoors and in vases in your home.

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