Lathyrus nervosus

Lathyrus nervosus is a perennial vine in the pea family, Fabaceae. Its common names include Lord Anson's pea and Lord Anson's blue pea. It comes from South America, including southern Brazil, Argentina, Chile, and Uruguay. Wild plants grow on coastal sands, gravel, and open grassland. In gardens, this climber suits beds, borders, and sheltered spaces.

Plants reach about 8–13 feet [2.5–4 metres] tall. Their spread is about 1.6–3.3 feet [0.5–1 metre]. They take two to five years to reach full size. The plant has soft, non-woody growth and sheds its leaves. Its grey-green leaves feel leathery and have clear veins. Each leaf ends in a tendril. Give the stems a support to climb, or let them scramble. Small groups of scented, purple-blue flowers grow on long stems in summer.

Choose a sheltered spot with full sun or light shade. A south-facing or west-facing site suits its needs. It needs fertile soil that drains well. It accepts chalk, clay, loam, and sand. Acid, neutral, and alkaline soils are all suitable. Keep the soil moist without leaving it waterlogged. RHS rates its hardiness as H3, suited to mild UK areas. PFAF lists USDA zones 8–11. Give it winter protection outside mild areas. Cut the stems down to ground level in autumn. Grow new plants from seed.

This vine suits cottage gardens, courtyard gardens, and beds beside walls. It also fits flower borders, patios, and containers. Its climbing growth lets gardeners use a support rather than leave it sprawling. The summer flowers add scent as well as colour. PFAF records its ability to fix nitrogen. Aphids, slugs, and snails may attack it. Possible diseases include powdery mildew, Fusarium wilt, and sweet pea viruses. These are reported risks, not signs that every plant will suffer.

Treat the pods and seeds as unsafe to eat. RHS warns that both people and pets must avoid eating them. It also advises gloves and other protection when handling the plant. PFAF lists cooked seeds as edible, but adds a strong caution. Its account says it found no toxicity records for this species. These sources therefore differ on seed safety. PFAF reports no known medicinal uses.