Gentiana clausa

Etymology

Gentians are named after King Gentius of Illyria, who is credited with discovering medicinal properties of the root; Clausa is Latin for “closed,” referring to the plant’s closed flower.

Native Habitat

Forests, meadows and fields, wood borders, stream banks, floodplains, and disturbed habitats. Its native range extends from ME south to the mountains of NC and TN, with rare occurrences in NY.

Garden Uses

Excellent choice for the edge of rain gardens, alongside streams, and any moist area in full sun to part shade.

Overview

A low-spreading perennial featuring lush dark green leaves and vibrant dark violet-blue flowers. The flowers do not open and are pollinated by insects that are strong enough to force their way in. Closed bottle gentian prefers well-drained, slightly acidic to alkaline soil in part shade to full sun. It grows 1 to 2 feet tall.

Spread

Above ground spread reaches 12-24 inches. Space plants 1 foot apart.

Leaves and Stems

Opposite, lance-shaped leaves line the usually unbranched stem.

Flowers

Densely packed clusters of deep violet-blue 1-2 inch long flowers, which always remain closed, bloom from late summer to fall. The majority of the tubular, erect flowers are clustered at the top of the stem. Upper flowers are supported by a whorl of leaves.

Fruit/Seed

The fruit is dry capsule (about 10 mm long) that splits open when ripe.

Wildlife Associates

Bumblebees are the main pollinators of this plant because they are strong enough to pry open the closed flowers.

Propagation

Propagate by seed or divisions of the root crown. Divide root crowns in fall or early spring and plant 1 foot apart. Be sure to include a large ball of soil around the division when you lift it out to protect the brittle crown. Seeds are collected just before the first hard freeze when the capsules begin to open and curl back. Tap seed out and store dry in sealed, refrigerated containers for up to four years. To prepare for planting, stratify seeds for a minimum of 60 days at 40°F in moist soil. These seeds require a cold period to germinate - a minimum of 60 days below 40°F in moist soil (or sand or vermiculite). Sow outdoors in pots, on the soil surface and leave uncovered from November through February. This species is challenging to grow, and is best for more experienced seed-sowers.