Bottle gentian

Sun

Full sun to partial shade; afternoon shade is helpful in warmer areas, especially if the soil might dry out.

Water

Keep the root zone consistently moist. Water deeply during dry spells; prolonged drought causes poor growth and scorched foliage.

Soil

Moist, humus-rich loam or clay that does not dry out. Tolerates periodically wet ground, but avoid stagnant, permanently submerged conditions.

Height

1-2 ft (0.3-0.6 m)

Spread

1-1.5 ft (0.3-0.45 m)

Flowers

Late summer to early autumn; blue to violet, bottle-shaped flowers clustered at stem tips and in upper leaf axils.

Foliage

Opposite pairs of dark green, lance-shaped leaves on upright stems; dies back in winter.

Growth

Slow to moderate; takes time to establish.

Care needed

Medium

• Pollinators
• Deer resistant
• Cold hardy
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Moderate

Toughness

Needs looking after

Pick your zone, country, light and whether you have pets.

1. Planting day

   1 ft (0.3 m)

2. After 1 year

   1.1 ft (0.34 m)

3. After 2 years

   1.2 ft (0.38 m)

4. After 3 years

   1.4 ft (0.42 m)

5. After 5 years

   1.5 ft (0.45 m)

   full size

About 4 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Native to

the US and Canada

Growth rate

Slow

• Plant in spring or early autumn while the soil is moist, keeping the crown at its original depth.
• Water during dry weather so the soil stays moist rather than drying between waterings.
• Apply a thin mulch of leaf mould or compost in spring, keeping it clear of the crown.
• Avoid heavy feeding; a light compost dressing is usually enough.
• Mark the planting position because shoots can emerge late in spring.
• Leave established clumps undisturbed rather than dividing them routinely.

Pruning. Cut dead stems to ground level in late winter or early spring before new shoots appear. Leave flower heads standing through autumn if you want seed.

Late winter

Cut back last year's dead stems without damaging the crown.

Spring

Plant nursery-grown plants and add a thin mulch of leaf mould or compost.

Late spring

Check for emerging shoots before weeding or digging nearby; protect young growth from slugs.

Summer

Water during dry spells and prevent vigorous neighbouring plants from crowding the clump.

Late summer

Keep plants evenly moist while they flower.

Autumn

Collect seed as capsules turn brown and begin to split; sow promptly outdoors.

• Plant small groups near the front or middle of a moist border, where the unusual closed flowers can be seen closely.
• Combine with cardinal flower and great blue lobelia beside a pond, above the permanently submerged zone.
• Use among sedges in a damp native meadow, with enough open space to prevent crowding.
• Place at a lightly shaded woodland edge for blue flowers after many spring woodland plants have finished.

Garden styles it suits: Native meadow, Woodland, Wildlife garden, Pollinator garden, Bog garden and Blues and silvers.

Plant it with: Cardinal flower, Great blue lobelia, Turtlehead, New England aster, Tussock sedge and Royal fern.

Wildlife: Bumblebees are its main pollinators; they push between the closed petals to reach nectar and pollen. It is generally less attractive to browsing deer than many border perennials, but it is not deer-proof.

• Slugs and snails can eat emerging shoots: check at dusk, remove pests and use an appropriate iron-phosphate bait if needed.
• Brown leaf edges, wilting or weak flowering often follow dry soil: water deeply and mulch to conserve moisture.
• Stems may lean in deep shade or overly rich soil: provide more light and avoid high-nitrogen fertilisers.
• Vigorous grasses and spreading perennials can overwhelm slow-establishing plants: keep nearby growth thinned until the clump is established.

Not known to be toxic to people, cats, dogs or horses, but species-specific safety information is limited. No particular part is established as poisonous; this is an ornamental plant, not a food plant, so do not eat it or allow pets to chew it.

• Soapwort gentian (Gentiana saponaria)

  Its blue flowers usually open slightly at the tip, exposing short lobes; bottle gentian flowers remain closed. Intermediate-looking plants can be difficult to identify from a distance.

• Yellow gentian (Gentiana flavida)

  Has pale cream to yellowish-white flowers rather than the blue-violet flowers typical of bottle gentian.

• Marsh gentian (Gentiana pneumonanthe)

  Has narrower leaves and blue trumpets that open into distinct spreading lobes rather than remaining bottle-shaped and closed.

The common name refers to the bottle-shaped flowers, which remain closed even when fully mature.

Propagation. Grow from fresh seed sown outdoors in autumn, allowing winter cold to break dormancy. Germination can be slow and uneven, and seedlings may take several years to flower. Division is possible in early spring but can set plants back; seed or nursery-grown plants are usually better choices.

Accepted botanical name

Gentiana andrewsii

In the US and Canada

Native in Canada and the lower 48 states.

Native range

Connecticut, Delaware, Illinois, Indiana, Iowa, Kansas, Kentucky, Manitoba, Maryland, Michigan, Minnesota and Missouri.

Measured

Soil pH 5.8 to 7.2. Average height 58 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.