Sweet Pea Perennial Vines

Characteristics

• Also called everlasting peas, perennial sweep peas are herbaceous perennials, meaning the plant dies back to ground level each year when cold weather arrives, and sends up new shoots the next spring. They're hardy in U.S. Department of Agriculture plant zones 3 or 4 though 7. Sweet peas love cool weather. They quickly reach 4 to 10 feet if given a suitable support to climb. Sweet pea flowers come in shades of pink, red, purple and white. Unlike their flashier annual cousins (Lathyrus odoroatus), they are not fragrant. Plants bloom in early summer in warm-weather areas and in midsummer in cooler climates.

Culture

• Grow perennial sweet peas in moist, well-drained soil in full sun for best flowering. These fast-growing vines need a strong support, but it must be small enough in diameter that the thread-like tendrils can wrap themselves around it securely. Sturdy garden twine or wrapped wire is ideal. Space plants 2 feet apart. Keep the vines deadheaded to extend the blooming period; once the plant begins to form seeds, flowering will decrease. In fall, cut the vines back to ground level once they've been blackened by frost; the plant puts up new flowering vines every year. You can start perennial sweet peas from seed or plant division, but it's best not to transplant them once they're established.

Cultivars

• Sweet pea seeds are available in mixed or individual colors, and starter plants are available in garden centers in the spring. Pink varieties include Pink Pearl and Splendens. Blushing Bride is a pink and white bi-color, while White Pearl, Snow White and Albus are all solid white. Red Pearl is red, as the name suggests, and Pink Beauty is a dark purple and red bi-color.

Warning

• Sweet peas produce long pods with pea-like seeds, but unlike edible garden peas, sweet pea seeds are poisonous if not prepared correctly. Be safe and never eat sweet pea seeds or pods. Symptoms of sweet pea poisoning include shallow breathing, convulsions, slow or weak pulse and paralysis. Plant sweet peas with caution in gardens accessible to young children and pets, and call 911 or poison control immediately if you think any part of the plant has been ingested.