Viola cucullata aka Blue Marsh Violet

Viola cucullata, or marsh blue violet, is a perennial wildflower in the violet family. It grows wild in eastern Canada and the eastern United States. Its habitats include wet meadows, swamps, springs, and open woods. It also grows beside streams and ponds. In North Carolina, it is most abundant in the mountains.

This low plant forms clumps and spreads from horizontal rhizomes. RHS gives a garden height and spread of 0.3–1.6 feet [0.1–0.5 metres]. The leaves form a low rosette at ground level. Each green, heart-shaped leaf has rounded teeth along its edge. Leaves can reach about 0.3 feet [0.09 metres] long. Their basal lobes fold inward, giving the species its name. The leaves grow larger after flowering, then die back seasonally.

Single blue to violet flowers open in late spring. Their long stalks hold them above all the leaves. Each flower spans about 0.07 feet [0.02 metres] and has five petals. The lowest petal has a short, stout nectar spur. A white patch and purple veins mark its front. Two lower outer petals bear hairs with club-shaped tips. Pale green seed capsules follow the flowers in summer. Each capsule splits into three parts when ripe, releasing seeds.

Grow marsh blue violet in rich soil with ample humus. It accepts clay, loam, sand, and chalk, across different soil pH levels. Sun, partial shade, and dappled shade can suit it. Keep the soil moist; this violet does not tolerate dry ground. RHS recommends moist soil that drains well. NC State also records tolerance of wet spells. Its hardiness ratings are USDA zones 3–7 and RHS H5. Plants take two to five years to reach full size.

Use it in borders, pots, rain gardens, or beneath shrubs. It also suits native gardens and provides ground cover. Bees and butterflies visit the flowers for nectar. Fritillary caterpillars feed on the leaves. Care needs are low, though slugs and snails may cause damage. Mites and violet gall midge may also attack it. Possible diseases include leaf spots, mildews, rust, and viruses. Young leaves and flower buds can be eaten raw or cooked. Leaves also make tea and can thicken soups. PFAF reports no known hazards. Its records of medicinal use describe tradition, not proven treatment.