Gentiana andrewsii

There isn’t much flowering in my southern Ontario garden as I write this in Mid October. A few asters, a couple of goldenrods, a few harebells (Campanula) and some Black-eyed Susans (Rudbeckia). One that stands out, however, is the Bottle Gentian (Gentiana andrewsii). This very late purple flowering plant with blossoms that stay tightly closed has been blooming for several weeks now. As usual, the Plant Description and In the Garden sections are courtesy of Shaun Booth from In Our Nature.

The tightly closed blossoms of Bottle Gentian are a lovely, though unusual, addition to the garden.

Scientific Name: Gentiana andrewsii

Common Name: Bottle Gentian

Family: Gentianaceae (Gentian Family)

Alternate Common Names: Andrew’s Gentian, Blind Gentian, Cloistered Heart, Closed Bottle Gentian, Closed Gentian, Fringe-top Bottle Gentian, Gall Flower, Prairie Closed Gentian, Sampson’s Snakeroot

Plant Description: Bottle Gentian has smooth, unbranched stems that are round and light green to purple. Opposite, stalkless leaves are found along the stem with the uppermost set of leaves being whorled. Leaves are broadly lanceolate, glossy on top and become larger as they ascend the stem, reaching up to 10 cm long and 5 cm wide. The stem terminates with a cluster of tubular flowers, but there may also be secondary flower clusters emerging from leaf axils. Each flower measures 2.5 cm to 4 cm long and has five fused petals with tiny teeth around their tips. The flowers never open and resemble closed buds even when in full bloom. Each flower turns into a papery capsule that splits open to release many tiny seeds. Each seed has papery wings that allow them to be carried by water or wind.

In the Garden: Bottle Gentian is valued by gardeners for its intriguing flowers and bold leaves. The flowers add a welcomed touch of blue to the late-summer garden, while the leaves take on shades of purple and burgundy in the fall. Bottle Gentian is not competitive, so choose its companions wisely. Slow growing but well worth the wait!

Skill Level: Beginner

Lifespan: Perennial

Exposure: Full sun to part shade

Soil Type: Humus-rich, slightly acidic, sandy loam

Moisture: Moist to wet

Height: 30–60 cm

Spread: 30-­50 cm

Bloom Period: Aug, Sept, (Oct)

Colour: Blue, purple

Fragrant (Y/N): N

Showy Fruit (Y/N): N     

Cut Flower (Y/N): Y

Pests: Mature plants are rarely bothered by foliar disease or leaf-chewing insects

Natural Habitat: Moist and shaded sites, meadows, damp prairies, and along shores

Wildlife Value: Especially valuable to bumblebees, just about the only insect with enough strength to force its way into the closed flower

Butterfly Larva Host Plant For: None

Moth Larva Host Plant For: Verbena Bud Moth (Endothenia hebesana)

USDA Hardiness Zones: 3–6

Propagation: Germination of seed requires cold, moist stratification for at least 60 days, and exposure to light (surface sow). Bottle Gentian are said to be difficult to start from seed, though William Cullina states that sowing outdoors in the fall produces excellent results. Some sources suggest plants may be propagated by dividing the root crowns in fall or early spring, but this is apparently tricky to do without killing the plant.

Bottle Gentian seeds are very tiny and should not be covered with soil as they need light to germinate.

Additional Info: Plant tends to lean at maturity, so plant among sturdier plants for support. If left undisturbed, plants in optimum growing conditions will naturalize over time into large clumps.

Native Range: (shaded area of map)