Calystegia soldanella aka Seashore False Bindweed

Calystegia soldanella, or sea bindweed, belongs to the Convolvulaceae family. It is native to Britain and Ireland. Its wider native range spans coasts in Europe and North Africa. It also reaches Asia, the Americas, and Australasia. It grows on sandy shores, shingle beaches, and dunes. An older scientific name is Convolvulus soldanella.

This low perennial trails across the ground and spreads through rhizomes. It reaches about 0.33 feet (0.1 m) tall. Its garden spread ranges from 1.6–3.3 feet (0.5–1 m). Plants take two to five years to reach full size. The stems are succulent, and the leaves have a kidney shape. It loses its leaves rather than keeping them year-round. Summer brings pink, trumpet-shaped flowers that face upwards. Each flower has five white stripes.

Sea bindweed needs full sun and an open site. Sandy soil with very free drainage suits its coastal needs. It accepts acid, neutral, or alkaline soil. Soil moisture can range from dry to moist. South-facing and west-facing sites suit it, including exposed spots. The RHS gives it a UK hardiness rating of H5. Plants For A Future lists USDA zones 5–9. These ratings describe hardiness within each source's own system.

Its low, spreading form suits coastal plantings and gravel gardens. It can also grow in cultivated beds with suitable conditions. Despite its link to bindweed, garden weed problems are unlikely. The RHS reports few disease problems, though slugs and snails may feed on it. It needs no pruning. Growers can raise plants from seed or divide the rhizomes. These traits do not remove its need for sharp drainage.

Plants For A Future lists leaves and young shoots as edible parts. Young shoots have been cooked as greens or pickled. They have also served as a substitute for samphire. Caution matters because the plant may have a purgative effect. The source gives both food and medicinal use low ratings. It records uses against scurvy, fever, and intestinal worms. It also lists diuretic, irritant, and purgative uses. These records do not establish safe treatment or safe portions. Flexible stems can serve as ties or simple string. Such ties have some strength but do not last long.