Delphinium carolinianum aka Carolina Larkspur

Delphinium carolinianum is also known as Carolina larkspur. It belongs to the buttercup family. This short-lived perennial lives for more than one year. It grows in clumps with upright flower stems. Kew gives its native range as central Canada to northeastern Mexico. In the United States, it grows in prairies, woods, and glades. It grows in moist woods and on dry, rocky slopes. Garden plants reach about 1–3 feet (0.3–0.9 metres) tall. They spread about 0.7–1.5 feet (0.2–0.46 metres) wide.

The gray-green leaves have deep cuts and lobes. Leaves at the base can form a rosette in winter. Leaves grow in turn on each side of the stem. They get smaller toward its tip. The upright stems are greenish white and have no branches. Fine hairs cover them. Each main stem ends in a flower cluster called a raceme. These clusters measure about 0.5–1 foot (0.15–0.3 metres) long. They can hold 30–40 blooms that open over three to four weeks.

Flowers bloom from April to June, though times vary by place. Most are blue or violet, but some are white. The small flowers have an uneven shape and four petals. Some sepals have a green mark near the tip. Bumblebees come for nectar. Butterflies and hummingbirds visit too. After bloom, each flower forms three joined pods called follicles. These turn from green to brown as they ripen. They split open to shed their seeds. Plants may reseed, then enter a rest phase after bloom.

Grow this larkspur in sun with soil that drains well. It accepts clay, loam, and sand, including neutral and alkaline soils. Missouri Botanical Garden advises rich soil kept moist to a moderate degree. NC State notes that it can also cope with dry sites. Cool summers suit it best. Shade in the afternoon helps in hotter places. It grows in USDA zones 4–7 but struggles with humid heat. Shelter from strong wind and storms helps protect the stems. Long flower stems may need stakes. Plants do not cope well with moves.

Use it in borders, cottage gardens, or groups left to spread. The blooms also serve as cut flowers. Deer and rabbits tend to leave it alone. Crown rot and botrytis blight can occur. So can leaf spot and powdery mildew. Aphids, mites, stem borers, and leaf miners may cause damage. Slugs and snails can also harm plants. All parts are toxic to people and animals if eaten. Eating them can cause severe gut problems. Contact can cause severe skin irritation. This is not an edible plant.