Thread-like, curling tendrils are the hallmark of sweet pea foliage. As the name suggests, many sweet pea varieties waft a gentle fragrance to complement their feminine, pastel-colored blooms. Both mounding and climbing varieties are simple to care for.
Choose a well-drained, full sun location for planting. Although these vines enjoy sunlight, they are not fans of intense heat. Your sweet pea may stop blooming altogether in very hot temperatures.
Create a trench about 10 inches deep, filled in with 5 inches of organic compost and 5 inches of soil with a modest amount of bonemeal mixed in. Soak the seeds in water overnight to soften the hull and produce quicker germination. Plant the seeds 2 inches apart at a depth of one inch. Water to keep the ground moist but not soggy.
Germination occurs in 2 to 4 weeks with blooms appearing at week 8. Thin the seedlings down to 5 or 6 inches in between. Mulch the top soil under plants to protect the roots from heat. Pinch spent blooms to encourage more flowering.
Provide a fence, trellis, or other support for sweet pea climbing varieties. Lathyrus odoratus, cultivar King Edward VII is an annual climber with a sweet fragrance. Lathyrus latifolius offers perennial climbing vines called Red, Pink, and White Pearl. Dwarf varieties Little Sweetheart and Supersnoop will not need staking as they grow low and bunchy.
Cut back annual sweet pea vines and compost them. Perennial vines will re-seed but may have trouble surviving through hard frosts. Mulch the top soil to protect them until spring.