Clematis — Virgin's-bower, Leatherflower

Three species in Delaware.

Two have flowers with white sepals.

Clematis terniflora, Japanese Virgin's-bower
Invasive non-native, Piedmont & coastal plain
Leaflets entire.

Clematis virginiana, Virginia Virgin-bower
Native, Piedmont & coastal plain
Leaflets toothed.

One has flowers with purple sepals.

Clematis viorna, Vase-vine Leatherflower
Rare native, Piedmont only

Sources: The Flora of Delaware, Weakley's Flora.