Are Sweet Pea Plants Perennial?

Sweet peas are a beloved garden flower known for their charming, colorful blooms that evoke thoughts of cottage gardens and summer romance. But one question that often arises with sweet peas is – are they perennial or annual plants? The answer is not quite straightforward, as some sweet pea varieties are perennial while others are annual. Let’s take a deeper look at the distinctions between perennial and annual sweet peas.

Annual vs. Perennial Sweet Peas

Annual sweet peas, with the botanical name Lathyrus odoratus, are the ones most gardeners are familiar with. These are the sweetly fragrant vintage varieties traditionally grown in English cottage gardens. Annual sweet peas only bloom for one season and then die off when cold weather arrives. They must be replanted from seed every spring.

Perennial sweet peas belong to a different species – Lathyrus latifolius. Also called everlasting pea or perennial pea vine, these are hardy, long-lived plants that come back year after year. The flowers of perennial sweet peas, while showy, lack the intense fragrance of annuals.

While annual sweet peas bloom in a diverse range of colors, perennials are mostly found in shades of pink, red and white. The foliage also differs – perennial sweet pea leaves are gray-green rather than bright green. When fall approaches, the above ground growth of perennial sweet peas dies back, but the plant overwinters and regrows the following spring.

Growing Habits

In terms of growing habits, perennial sweet peas are vigorous, sprawling vines that can reach lengths of 6 to 10 feet. They climb by wrapping their tendrils around any available support. Trellises, fences and arbors are ideal structures for displaying these carefree vines.

Annual sweet peas also climb but are generally shorter, topping out around 6 feet. Both annual and perennial sweet peas produce attractive pea-like flowers from summer through early fall. Deadheading spent blooms encourages more flowering.

Perennial Sweet Pea Benefits

So why choose perennial over annual sweet peas? Perennials offer several advantages:

• Hardy and tough – can withstand cold winters and cope with some drought

• Fast growing and carefree once established

• Provide color in the garden for many years with little fuss.

• Tolerant of a wide range of soils and growing conditions.

• Attract bees, butterflies and hummingbirds.

• Add vertical interest against fences, arbors, trellises.

• Good for screening unsightly views and creating privacy.

• Can be grown in containers on porches, patios, decks.

For gardeners seeking a season-long display of cottage garden charm with minimal effort, perennial sweet peas are the way to go. A few plants can provide years of enjoyment. Simply provide full sun to partial shade, average soil and regular watering for the best results.

Growing Perennial Sweet Peas

Here are some helpful tips for successfully growing perennial sweet peas:

• Choose a sunny, well-draining spot. Avoid soggy soil.

• Prepare soil by mixing in compost or aged manure before planting. Sweet peas need nutrient-rich soil.

• Sow seeds outdoors in spring after the last frost. Seeds can also be started indoors 4-6 weeks before transplanting seedlings outside after danger of frost has passed.

• Plant seeds 1 inch deep and 6 inches apart if sowing directly in the garden.

• Water plants regularly until established. Mature plants are quite drought tolerant.

• Install supports like trellises and wire fencing at planting time. Once vines start climbing, they will latch on with their tendrils.

• Apply a balanced organic fertilizer or compost tea monthly during the growing season.

• Remove spent flowers to encourage more blooms.

• In cold winter areas, cut back vines to the ground after frost. Apply mulch if desired.

Choosing a Perennial Sweet Pea Variety

Many beautiful perennial sweet pea varieties are available. Here are some top choices:

• Pink Pearl – Prolific blooms in soft pink. The most popular variety.

• Red Pearl – Vivid red blossoms.

• White Pearl – Pure white, delicate flowers.

• Spring Sunshine – Cheerful yellow blooms. Unusual for a perennial sweet pea.

• Blue Moon – Lavender-blue blooms with white centers.

• Cupani – An heirloom vine with large, frilly pink and maroon flowers.

• Black Knight – Deep reddish-purple flowers. Named for its dark stems and leaves.

Whether grown in flower beds, borders or containers, perennial sweet peas add old-fashioned charm and romance to gardens. For low maintenance beauty that lasts, look no further than these delightful heritage vines. Any garden is made lovelier with their presence.

Common Questions about Perennial Sweet Peas

Are perennial sweet pea flowers edible?

No, do not eat the flowers or seeds, as they contain toxic compounds and can cause illness if ingested.

Do perennial sweet peas spread aggressively?

They can spread by self-seeding if not deadheaded. Limit spread by clipping off spent blooms. Established plants can also spread via underground rhizomes.

Should perennial sweet peas be cut back for winter?

In cold climates, trim vines back to 6 inches after frost. In mild winter areas, leave some top growth for protection. Apply mulch around base if desired.

How much sun do perennial sweet peas need?

They thrive in full sun but can tolerate partial shade, especially in hot southern climates. At least 6 hours of direct sun daily is ideal.

Are perennial and annual sweet peas related?

Yes, they belong to the same legume family (Fabaceae) but are different species. Annual sweet peas are Lathyrus odoratus while perennial sweet peas are Lathyrus latifolius.

What is the best way to grow perennial sweet peas?

Provide sunny location, fertile soil, trellises for climbing support and regular watering. Fertilize monthly and remove spent blooms to encourage more flowers.

Final Thoughts

Sweet peas are treasured for their olde-world charm and exquisite colors. While annual varieties reign supreme for fragrance, perennial sweet peas deserve a spot in gardens too for their resilient, carefree nature. Once established, they continue providing beauty year after year. Their vining habits also make them useful for screening and vertical interest. For non-stop flowers with vintage appeal, look no further than hardy, easy-care perennial sweet pea vines.