Stemless gentian
Gentiana acaulis · Gentianaceae
Huge, upturned trumpets of the deepest, purest blue in the plant world sit directly on a mat of small, glossy leaves in spring.
- Size
- 4 in tall, 12 in wide
- Zones
- 3 to 7
- Light
- Full sun to part sun
- Flowers
- Early May to early June
- Pets
- No toxicity recorded
- Job in a bed
- Carpet
A bed built around stemless gentian
The planner designed this bed around stemless gentian when this page was made: a 12 × 6 ft (3.7 × 1.8 m) English border in zone 6, full sun. It chose the other plants from the 966 that suit those conditions, and says below why stemless gentian stands where it does.
The plants
- 1 Stemless gentian × 23, blue
- 2 Carpathian bellflower × 8, white
- 3 Little bluestem 'The Blues' × 5, tan
- 4 Stiff goldenrod × 3, yellow
- 5 Dwarf English boxwood × 1, dark green leaves
- 6 Pearly everlasting × 3, white
- 7 Star of Persia × 3, purple
- 8 Spring starflower × 12, blue
Why this plant
- The only trumpets. The others are bells, spires, flat plates and others. Shape reads at a distance, where colours blur.
- A classic partner for Carpathian bellflower. Both are on this plan. A pairing gardeners have proved outranks a general rule.
Why here
- Under the taller plants. It runs back between them as living mulch: there its job is to cover the soil, not to be looked at.
- 23 plants in 6 groups (5, 5, 4, 3, 3 and 3). Seen again further along, the same plant ties the bed together.
- Beside Carpathian bellflower. A recognised partner: the planner puts such plants together where it can.
Why now
- In flower for five weeks. From early May to early June.
- Fills a gap. For two of those weeks nothing else on the plan is in flower.
- One of two evergreens. They are what the bed has to show from November to March.
Planned as an English border: 6 of the 6 groups (100%) are drifts, longer along the bed than they are deep. The scheme leans cool (blue and purple) and uses yellow for warmth, with white and tan to calm things between them. When the flowers are over, three kinds, among them stemless gentian and little bluestem 'The Blues', keep the bed from looking bare.
The planner's own design check: 13 Excellent, 4 Good. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where stemless gentian goes in a border
At 4 in it belongs at the front of a bed. In the planner's ten height classes it is ground-hugging (up to 6 in).
Its job: carpet. A groundcover planted in threes and fives to cover the soil: along the front, and just behind it.
The blue that all others are measured against. It is notoriously fickle about flowering: it wants cool summers, firm, moist, gritty soil and full light. Where it is happy, do not disturb it.
- Rock gardens and troughs in cool climates
- The purest blue
- Edging in firm, moist soil
What to plant with stemless gentian
Plants recorded as good partners for it, and what each pairing does:
- English primrose: happy in the same moist soil.
- Carpathian bellflower: takes over when it finishes, flowering from late June; tall enough (10 in) to stand behind it.
- Mountain avens: in flower together for three weeks, from late May.
Questions about stemless gentian
Does stemless gentian need sun or shade?
Stemless gentian grows in full sun (6 or more hours of direct sun a day) and part sun (4 to 6 hours of sun, including some afternoon sun).
It wants soil that stays evenly moist, of average fertility, and a good soak in dry spells.
What zones does stemless gentian grow in?
USDA zones 3 to 7. It is hardy to zone 3, which means it survives winter nights down to about −30 °F (−34 °C).
Above zone 7 it struggles: the zones measure winter cold, but a plant's top zone usually means the summers are too hot or the winters too mild for it to rest.
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does stemless gentian flower in my zone?
In zone 5 it flowers early May to early June. As a spring flower it moves about a week for every zone: earlier where it is warmer, later where it is colder.
| Zone 3 | Late May to mid June |
|---|---|
| Zone 4 | Mid May to mid June |
| Zone 5 | Early May to early June |
| Zone 6 | Early May to early June |
| Zone 7 | Late April to late May |
Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.
How far apart should stemless gentian be planted?
10 in (25 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 12 in (30 cm), so a group knits into one patch.
It grows 4 in (10 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many stemless gentian plants do I need?
At 10 in apart, set out in staggered rows:
- 17 to fill 10 square feet (about 1 m²)
- 13 for a single row 10 ft (3 m) long
- 55 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as threes and fives, along the front and just behind it.
In the bed above, the planner used 23 in six groups.
Is stemless gentian poisonous to dogs and cats?
No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension.
"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.
Do deer eat stemless gentian?
Mostly not. NC State lists it as resistant to rabbits. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.
What flowers after stemless gentian?
Stemless gentian is over by early June. These start as it finishes and carry the same spot on, so it never goes flat:
- Carpathian bellflower: from late June to late August, 10 in tall (a recorded partner).
- Creeping thyme: from early June to mid July, 3 in tall.
- Lady's mantle: from late May to early July, 18 in tall.
What does stemless gentian look like in winter?
Stemless gentian keeps its dark green leaves all winter, so it is one of the plants that hold a bed together from November to March, when the perennials have gone.
Is stemless gentian good for bees and butterflies?
Stemless gentian is visited by pollinators and bees.
More Gentiana
- Bottle gentian Gentiana andrewsii
- Crested gentian Gentiana septemfida
- Willow gentian Gentiana asclepiadea
In these guides
- Rabbit-resistant plants
- Pet-safe plants for a sunny border
- Plants for bees
- Low plants for the front of a border
- Groundcover plants
- Evergreen perennials, ferns and grasses
- Plants with blue flowers
Every fact on record
- Type
- Perennial (groundcover)
- Size
- 4 in (10 cm) tall, 12 in (30 cm) wide
- Plant
- 10 in (25 cm) apart
- Height class
- Ground-hugging (up to 6 in)
- Place in the bed
- Front
- Flowers
- Early May to early June; trumpets; blue
- Leaves
- Fine texture, evergreen; dark green
- Shape
- Mat-forming, clumping
- Hardy in
- USDA zones 3 to 7
- Light
- Full sun, part sun
- Soil
- Average, evenly moist
- Water
- Moderate
- Feeding
- None needed
- Family
- Gentianaceae
- Comes from
- Northeast Spain to the Alps, Central Italy to Carpathians
- Attracts
- Pollinators, bees
- Stands up to
- Rabbits
Checked against NC State Extension. Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.