Rocky Mountain columbine
Aquilegia caerulea ·
Large, upward-facing flowers of sky blue and white with long spurs: the state flower of Colorado. It is short-lived and best in cool summers.
- Size
- 24 in tall, 18 in wide
- Zones
- 3 to 8
- Light
- Full sun to part shade
- Flowers
- Late May to late June
- Pets
- Toxic (mild)
- Job in a bed
- Weaver
A bed built around Rocky Mountain columbine
The planner designed this bed around Rocky Mountain columbine when this page was made: a 12 × 6 ft (3.7 × 1.8 m) cottage garden in zone 6, part sun. It chose the other plants from the 708 that suit those conditions, and says below why Rocky Mountain columbine stands where it does.
The plants
- 1 Rocky Mountain columbine × 4, blue
- 2 Woodland strawberry × 13, white
- 3 Coral bells 'Firefly' × 11, red
- 4 Brown-eyed Susan × 5, yellow
- 5 Purple milkweed × 5, purple
- 6 Inkberry 'Gem Box' × 1, dark green leaves
- 7 Iris 'Katharine Hodgkin' × 12, blue
- 8 Daffodil 'Tete-a-Tete' × 12, yellow
Why this plant
- The only bells. The others are open bowls, airy sprays, daisies and others. Shape reads at a distance, where colours blur.
Why here
- In the middle. At 24 in it is the step between coral bells 'Firefly' (10 in) in front and inkberry 'Gem Box' (2½ ft) behind: each is seen over the one before.
- 4 plants in 4 places. An accent is a punctuation mark: the repeat along the bed gives it rhythm.
- Fine leaf against bold. Purple milkweed is beside it: the strongest contrast of leaf there is.
Why now
- In flower for five weeks. From late May to late June.
- Part of the bed's peak. With woodland strawberry, coral bells 'Firefly' and purple milkweed in early June: 4 kinds at once. No week has more.
Planned as a cottage garden: 39 of the 39 plants (100%), bulbs aside, stand alone or in groups of no more than five, small enough for the kinds to mingle. Neither end outweighs the other: the visual weight is split 53 to 47, left to right. The front edge is finished with coral bells 'Firefly' and woodland strawberry.
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 Rocky Mountain columbine goes in a border
At 24 in it belongs in the middle of a bed. In the planner's ten height classes it is medium short (18 to 24 in).
Its job: weaver. A light, airy plant threaded singly between sturdier ones to knit the planting together.
The most elegant columbine, but it resents heat and lasts only a few years. Let it seed, or replant; in hot-summer regions choose the golden columbine instead.
- Cool-climate borders and rock gardens
- Blue and white for late spring
- Cut flowers
What to plant with Rocky Mountain columbine
Plants recorded as good partners for it, and what each pairing does:
- Lupine: blue against yellow, opposite each other on the colour wheel, if you choose those colours, in flower together for five weeks; tall enough (3½ ft) to stand behind it.
- Siberian iris: in flower together for four weeks, from late May.
- Cranesbill 'Rozanne': in flower together for three weeks, from early June.
Questions about Rocky Mountain columbine
Does Rocky Mountain columbine need sun or shade?
Rocky Mountain columbine grows in full sun (6 or more hours of direct sun a day), part sun (4 to 6 hours of sun, including some afternoon sun) and part shade (2 to 4 hours of sun, mostly in the morning).
It wants ordinary well-drained soil, of average fertility, and a good soak in dry spells.
What zones does Rocky Mountain columbine grow in?
USDA zones 3 to 8. It is hardy to zone 3, which means it survives winter nights down to about −30 °F (−34 °C).
Above zone 8 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 Rocky Mountain columbine flower in my zone?
In zone 5 it flowers late May to late 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 | Early June to late June |
|---|---|
| Zone 4 | Late May to late June |
| Zone 5 | Late May to late June |
| Zone 6 | Mid May to late June |
| Zone 7 | Early May to mid June |
| Zone 8 | Early May to mid June |
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 Rocky Mountain columbine be planted?
12 in (30 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 18 in (45 cm), so a group knits into one patch.
It grows 24 in (60 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many Rocky Mountain columbine plants do I need?
At 12 in apart, set out in staggered rows:
- 12 to fill 10 square feet (about 1 m²)
- 11 for a single row 10 ft (3 m) long
- 38 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as one at a time, threaded between sturdier plants.
In the bed above, the planner used four in four groups.
Is Rocky Mountain columbine poisonous to dogs and cats?
Yes: mild toxicity to people, dogs and cats. Seeds and roots can cause stomach upset if eaten, and the sap may irritate skin.
Is there a pet-safe plant like Rocky Mountain columbine?
These come closest to doing what Rocky Mountain columbine does, and no toxicity is recorded for them:
- Peach-leaved bellflower: the same colour; an accent, not a weaver, 6 in taller.
- Balloon flower: the same size and the same colour; a drift, not a weaver, flowers early July to mid August.
Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.
Will Rocky Mountain columbine spread?
It seeds itself about; the risk of it taking over is moderate. Short-lived, but keeps going by self-seeding. Thin or move seedlings where they are not wanted.
What flowers after Rocky Mountain columbine?
Rocky Mountain columbine is over by late June. These start as it finishes and carry the same spot on, so it never goes flat:
- Astilbe: from late June to mid July, 24 in tall.
- Black-eyed Susan: from mid July to mid September, 24 in tall.
- Butterfly weed: from late June to early August, 24 in tall.
What does Rocky Mountain columbine look like in winter?
Rocky Mountain columbine dies down to the ground and there is nothing to see until spring. The old stems can be cut in autumn, or left until spring as shelter for overwintering insects.
More Aquilegia
- Columbine Aquilegia
- Columbine 'Nora Barlow' Aquilegia vulgaris 'Nora Barlow'
- European columbine Aquilegia vulgaris
- Fan columbine Aquilegia flabellata
- Golden columbine Aquilegia chrysantha
- Wild columbine Aquilegia canadensis
In these guides
- Garden plants toxic to cats
- Garden plants toxic to dogs
- Native plants for shade
- Plants with blue flowers
Zone guides: Zone 3 · Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8
Every fact on record
- Type
- Perennial
- Size
- 24 in (60 cm) tall, 18 in (45 cm) wide
- Plant
- 12 in (30 cm) apart
- Height class
- Medium short (18 to 24 in)
- Place in the bed
- Middle
- Flowers
- Late May to late June; hanging bells; blue, white
- Leaves
- Fine texture, herbaceous; blue-green
- Shape
- Upright, self-seeding
- Hardy in
- USDA zones 3 to 8
- Light
- Full sun, part sun, part shade
- Soil
- Average, well-drained
- Water
- Moderate
- Feeding
- Light, in spring
Not yet checked against an outside reference: its figures rest on general horticultural knowledge. 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.