Delicious scent, lovely flowers, and vining or bush habit earn these a place in gardens all over the West. You will often find flowers described as “sweet pea–shaped”: each blossom has one large, upright, roundish petal (banner or standard); two narrow side petals (wings); and two lower petals that are somewhat united, forming a boat-shaped structure (keel).
To hasten germination, soak seeds for a few hours before planting. In less-than-perfect soil, prepare the ground by digging a 1–1 1/2-ft.-deep trench. Mix 1 part peat moss or other organic soil amendment to 2 parts soil, also adding a complete fertilizer according to label directions; backfill trench with mix.
Sow seeds 1 in. deep and 1–2 in. apart. When seedlings are 4–5 in. high, thin to at least 6 in. apart. Pinch out tops to encourage strong side branches. Where climate prevents early planting or soil is too wet to work, start three or four seeds in each small peat pot, indoors or in a protected place, and set out when weather has settled. Plant peat pots 1 ft. apart, thinning each to one strong plant. This method is ideal for bush types.
Protect young seedlings from birds and control slugs and snails. Never let vines dry out. To prolong bloom, cut flowers at least every other day and remove all seedpods. Regular monthly feeding will keep vines vigorous and productive. For vining sweet peas, provide a trellis, strings, or wire before planting. Seedlings need support as soon as tendrils form. A freestanding trellis running north and south is best. When planting against a fence or wall, keep supports away from the structure to ensure good air circulation.
Annual, native to the Mediterranean region. Blooms in winter, spring, or summer, bearing many spikelike clusters of crisp-looking flowers with a clean, sweet perfume. Blossoms come in single and mixed colors. Mixes include deep rose, blue, purple, scarlet, white, cream, salmon, bicolors.
Vining types grow to 5 ft. or more; bush kinds grow 8 in. to 3 ft. tall. Sweet peas make magnificent cut flowers in quantity.