10 BLACK KNIGHT SWEET PEA Lathyrys Odoratus Flower Vine Seeds by Seedville BLOOM TIME: Late Spring - Mid Summer HARDINESS ZONE: Annual PLANT HEIGHT: 4 - 6 Foot Vine . . . PLANT SPACING: 6 - 9" LIGHT REQUIREMENTS: Sun . . . SOIL / WATER: Average Black (Deep Maroon). Sweet Peas are fragrant and make a great cut flower. This heirloom variety tolerates heat well and will attract bees, birds, and butterflies.