Clematis crispa aka Curly Clematis

Clematis crispa is a perennial vine in the buttercup family. Common names include blue jasmine, marsh clematis, and curlflower. It comes from the central and southeastern United States. Wild plants grow in swamps and on floodplains. The vine can climb or spread across the ground. Garden plants reach about 5–10 feet [1.5–3 metres] tall. Reported spreads range from 3–8 feet [0.9–2.5 metres]. It grows fast and often dies back in winter.

The stems are partly woody and climb by twining. Young stems start green, then turn reddish brown. Older bark forms long splits as it ages. The dark green leaves fall with the change of season. Compound leaves have three to five oval leaflets. Their edges are smooth, and their surfaces lack hairs. These leaves form a green backdrop for the blooms. Small brown seeds carry long, silky tails. They form loose heads that add interest after flowering.

The flowers hang down like small bells and have a light scent. Their pale blue to violet outer parts surround white interiors. Curled sepal edges give the blooms their distinct shape. Most flowers measure one to two inches across. Bloom dates vary among the sources and growing regions. Missouri Botanical Garden gives May through July as its main season. Other accounts describe spring blooms, summer flowers, and a fall return. Bees, butterflies, and other insects visit the flowers.

Full sun gives the best bloom, though plants accept part shade. Keep the soil moist, but allow excess water to drain. Mulch or nearby plants can shade and cool the roots. Sources list clay, loam, sand, and chalk as suitable soils. Soil pH guidance differs: NC State favors acid soil. RHS lists neutral and alkaline soils as suitable. The plant tolerates heat and suits USDA zones 6–9. RHS gives it a UK hardiness rating of H6. Grow it on a fence, wall, arbor, or trellis. Without support, it can cover ground or weave through shrubs.

Moist native gardens and beds near water suit this vine. It suffers less deer damage than some other clematis. Sources also report tolerance of black walnut and rabbits. Clematis wilt can kill affected plants. Other risks include mildew, leaf spots, rust, and slime flux. Aphids, slugs, snails, and caterpillars may cause damage. RHS places it in pruning group 3. Layering and semi-hardwood cuttings offer ways to raise new plants. This is not a plant to eat. It can irritate human skin and harm pets that eat it.