Calystegia soldanella
sea bindweed
Coastal temperate and subtropical regions worldwide
Overview
Calystegia soldanella is a low, trailing perennial of the bindweed family, found almost exclusively on coastal sand. Unlike its climbing relatives, it creeps flat across the ground on slender stems that root at intervals and rise from a deep, far-running rhizome buried in the dune. The fleshy, kidney-shaped leaves are 0.4-1.6 inches (1-4 cm) wide, glossy and somewhat leathery, an adaptation to salt spray and drought. From June to August it produces solitary funnel-shaped flowers 1.5-2 inches (4-5 cm) across, pale to deep pink with five paler radiating stripes and a white throat. Each flower opens for a single day. The plant binds shifting sand with its rhizomes and tolerates burial, salt, and intense sun. It rarely grows away from the coast and declines where dunes are stabilised or trampled. Its deep, brittle rhizomes make established plants hard to move or remove. The seeds are buoyant and salt-tolerant, dispersing along the strandline by sea.
Native Range
Native to coastal dunes and shingle across much of the temperate and subtropical world, including Europe, Asia, Australasia, and the Americas, almost always on sand within reach of the sea.Suggested Uses
Grown in coastal and seaside gardens, sand beds, and dune-restoration schemes, where it stabilises bare sand and adds summer flower. It suits gravel gardens that mimic free-draining maritime conditions. It is planted as spaced rhizome sections rather than in dense blocks, as it spreads underground.How to Identify
Appearance
Size & Dimensions
Height2" - 6"
Width/Spread1' - 3'
Reaches mature size in approximately 3 years
Bloom Information
Flowering runs from June to August, each pink funnel-flower opening for a single day. The flowers draw bees and other long-tongued insects to nectar at the base of the tube. Flattened seed capsules follow, releasing a few large, buoyant seeds that float in seawater.
Detailed Descriptions
Foliage Description
greenGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Sea bindweed grows in full sun on deep, sharply drained sand, and depends on the open, mobile conditions of coastal dunes. It tolerates salt spray, sand burial, and drought but fails in rich, moisture-retentive, or shaded garden soil. Propagation is by seed, which germinates better after the hard coat is nicked, or by sections of rhizome. In cultivation it needs a sand bed or deep gritty mix and full exposure to do well. It is intolerant of disturbance once its deep rhizomes are established. Excess water and competition from vigorous plants are the main causes of failure.Pruning
No pruning is required. Trailing stems can be trimmed back where they spread beyond their allotted space, though the plant regrows from the rhizome. Removing seed capsules before they ripen limits self-sowing in mixed sand plantings.Container Growing
✓ Suitable for container growing
Minimum container size: 5 gallons