How Long Does a Sweet Pea Plant Bloom?

Varieties

• Sweet peas are traditionally grown as an annual. Several varieties are available, including heirlooms, with smaller blooms and sweeter fragrance. Modern varieties are meant either for winter blooms or late spring to early summer blooming. Native to parts of the Mediterranean including Crete, Italy and Sicily, sweet peas are relatively cold hardy, with varieties that are hardy all the way to U.S. Department of Agriculture plant hardiness zone 2. Some varieties are also heat resistant. They are not, however, heat proof, and hot summer temperatures can put an end to their blooms. Heirloom varieties do demonstrate more heat tolerance than modern varieties, but in hot, humid areas they may decline and die. Pea pods are poisonous.

Bloom Time

• The spring- and summer-flowering varieties, which bloom from mid-spring to early or midsummer, usually begin blooming in May. In warmer climates, they might begin blooming a bit earlier. Earlier varieties bloom in winter in mild climates and as a very early spring flower elsewhere. Bloom time depends on the amount of daylight available. Winter varieties need at least 10 hours of daylight to bloom, whereas later spring and early summer varieties need more like 12 to 15 hours.

Bloom Length

• Sweet pea usually blooms for a few months. Later varieties of sweet pea begin blooming in May and are finished around July, but they can go longer if weather remains cool, as heat is a limiting factor on flowering. Winter varieties will bloom as long as they have the proper amount of sunlight and do not freeze, though frost will not kill them. Deadheading the spent blooms will prolong the bloom time.

Appearance and Culture

• Sweet peas come in almost every color except yellow, including red, orange, pink, purple, white, blue and lavender. With support such as a trellis, sweet peas can grow to between 3 and 8 feet and spread 2 to 3 feet. They prefer rich, moist soil and do best with compost incorporated into their planting bed. Grow them in full sunlight. Best bloom performance, and performance overall, occurs earlier in the season or in areas where summers are cool and relatively dry. In hot, humid areas, you can extend bloom time by mulching plants to conserve soil moisture.