Sweet pea

Lathyrus odoratus

Sweet peas climb and give scented flowers to cut from early summer. Give them canes, netting or a fence to climb. Pinch out the tip when they are about 10 cm tall and the plants grow bushier. The one rule: keep picking, because once seed pods form they stop flowering. The pods look like garden peas, but they are poisonous.

Looking after it

Water: They need a lot of water. Keep the soil moist all season and water well in dry spells. Dry roots cut the flowering short. In warm weather, pots need water every day. Feeding: Average feeding is right for sweet peas. Before sowing or planting, dig in plenty of compost or well-rotted manure. Once they are growing, a liquid feed every week or two keeps the flowers coming.

Cutting and after flowering

Every few days, cut stems in the morning when the lowest flowers on them are open. Take off any seed pods you find, or the plant stops flowering. Cut stems last a few days in a vase. The more you cut, the more new flowers come.

What can go wrong

Aphids. Green insects on the shoot tips and buds can spread viruses that streak and twist the plant. Squash them or hose them off early. Pull out any plants with streaked, stunted growth.
Powdery mildew. Late in summer the leaves get a white, dusty coat, worse in dry soil and in crowded spots with still air. Water in dry spells and keep the air moving. Cut out the affected growth.
Buds falling off. After cold nights or when the roots are dry, the flower buds turn yellow and fall before they open. Keep the soil moist. It usually stops once the weather settles.

Growing facts: RHS, UC ANR and seed-company sowing guides. Sweet pea care: RHS. pH: University of Missouri extension. Powdery mildew: Oregon State University extension.