Camassia
Camassia leichtlinii ·
Tall spires of starry blue flowers in late spring, on a bulb that tolerates heavier and damper soil than most. It goes dormant by midsummer.
- Size
- 2½ ft tall, 8 in wide
- Zones
- 4 to 8
- Light
- Full sun to part sun
- Flowers
- Mid May to late May
- Pets
- Not checked
- Job in a bed
- Accent
A bed built around camassia
The planner designed this bed around camassia 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 camassia stands where it does.
The plants
- 1 Common thyme × 8, lavender
- 2 Sedum 'Lidakense' × 25, pink
- 3 Little bluestem 'The Blues' × 3, tan
- 4 Swamp milkweed 'Ice Ballet' × 3, white
- 5 Inkberry 'Gem Box' × 1, dark green leaves
- 6 Blanket flower 'Mesa Yellow' × 3, yellow
- 7 Camassia × 3, blue
- 8 Star of Persia × 2, purple
Why this plant
- The only blue.
Why here
- In the middle. At 2½ ft it is the step between common thyme (10 in) in front and little bluestem 'The Blues' (3 ft) behind: each is seen over the one before.
- A step in the back row. Next to little bluestem 'The Blues' (3 ft) and blanket flower 'Mesa Yellow' (18 in): no two neighbours there are the same height, so the back steps up and down like a skyline.
- 3 plants in 3 places. An accent is a punctuation mark: the repeat along the bed gives it rhythm.
Why now
- In flower for three weeks. From mid May to late May.
- Opens the season. In its first week nothing else on the plan is in flower.
- Leaves gone by midsummer. They die back and leave bare ground. A perennial that comes up late stands beside it, and grows over the gap.
Planned as an English border: 5 of the 6 groups (83%) are drifts, longer along the bed than they are deep. Cool colours (lavender, pink, blue and purple) with yellow as the warm note, and tan and white to calm things between them. Little bluestem 'The Blues' and swamp milkweed 'Ice Ballet' anchor the back corners of the bed: the tallest plants on the plan stand there.
The planner's own design check: 12 Excellent, 5 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 camassia goes in a border
At 2½ ft it belongs in the middle of a bed. In the planner's ten height classes it is medium (24 in to 2½ ft).
Its job: accent. An upright plant used singly, like a punctuation mark, and repeated at intervals to give the bed rhythm.
It fills the gap after the daffodils and before the summer perennials, and unlike most bulbs it tolerates heavy, damp soil. Plant it among later perennials that will cover its fading leaves.
- Blue spires in late spring
- Damp soil and meadow grass
- Following on from daffodils
What to plant with camassia
Plants recorded as good partners for it, and what each pairing does:
- Siberian iris: grows up in time to hide its dying leaves; happy in the same moist soil.
- Daylily: takes over when it finishes, flowering from late June; grows up in time to hide its dying leaves.
- Cranesbill 'Rozanne': takes over when it finishes, flowering from early June; grows up in time to hide its dying leaves; a low mound at the foot of its spires.
Questions about camassia
Does camassia need sun or shade?
Camassia 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 camassia grow in?
USDA zones 4 to 8. It is hardy to zone 4, which means it survives winter nights down to about −20 °F (−29 °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 camassia flower in my zone?
In zone 5 it flowers mid May to late May. As a spring flower it moves about a week for every zone: earlier where it is warmer, later where it is colder.
| Zone 4 | Late May to early June |
|---|---|
| Zone 5 | Mid May to late May |
| Zone 6 | Early May to late May |
| Zone 7 | Early May to mid May |
| Zone 8 | Late April to early 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 camassia be planted?
8 in (20 cm) apart, from the middle of one plant to the middle of the next. That is about its full width, so each plant keeps its own outline.
It grows 2½ ft (75 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many camassia plants do I need?
At 8 in apart, set out in staggered rows:
- 27 to fill 10 square feet (about 1 m²)
- 16 for a single row 10 ft (3 m) long
- 86 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as one at a time, repeated along the bed at intervals; a slender one reads better as a clump of three.
In the bed above, the planner used three in three groups.
What can I plant to hide camassia's leaves after it flowers?
A bulb's leaves have to be left to yellow for about six weeks after flowering, to feed next year's flowers. Plant it among perennials that come up late and spread wide, and they grow over the leaves as they fade:
- Daylily: 2½ ft tall and 24 in wide, a recorded partner, in flower late June to early August.
- Cranesbill 'Rozanne': 18 in tall and 24 in wide, a recorded partner, in flower early June to early October.
- Catmint 'Walker's Low': 24 in tall and 2½ ft wide, in flower mid May to mid September.
What does camassia look like in winter?
Camassia is underground: it dies back after flowering and waits as a bulb until spring. Mark where it is, so a fork does not find it first.
More Camassia
- Quamash Camassia quamash
In these guides
Zone guides: Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8
In flower in: May
Every fact on record
- Type
- Bulb
- Size
- 2½ ft (75 cm) tall, 8 in (20 cm) wide
- Plant
- 8 in (20 cm) apart
- Height class
- Medium (24 in to 2½ ft)
- Place in the bed
- Middle
- Flowers
- Mid May to late May; upright spires; blue, white
- Leaves
- Fine texture, summer-dormant; green
- Shape
- Upright, clumping
- Hardy in
- USDA zones 4 to 8
- Light
- Full sun, part sun
- Soil
- Average, evenly moist
- Water
- Moderate
- Feeding
- None needed
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.