Columbine

Questions about columbine

Does columbine need sun or shade?

Columbine grows in 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 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 columbine flower in my zone?

In zone 5 it flowers early May to mid June. As a spring flower it moves about a week for every zone: earlier where it is warmer, later where it is colder.

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 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 16 in (40 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 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 five in five groups.

Is 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.

Rated from NC State Extension. Where references disagree, the more cautious rating is used.

Is there a pet-safe plant like columbine?

These come closest to doing what 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 columbine spread?

It seeds itself about; the risk of it taking over is moderate. Short-lived but self-seeds freely, and seedlings may not match the parent's colour.

What flowers after columbine?

Columbine is over by mid June. These start as it finishes and carry the same spot on, so it never goes flat:

• Foxglove: from early June to mid July, 4 ft tall (a recorded partner).
• Astilbe: from late June to mid July, 24 in tall.
• Black-eyed Susan: from mid July to mid September, 24 in tall.

What does columbine look like in winter?

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.