Stokes' aster
Stokesia laevis · Asteraceae
Large, fringed flowers like a cornflower crossed with an aster, in lavender-blue, purple or white, through the summer. A native of the Southeast.
- Size
- 18 in tall, 18 in wide
- Zones
- 5 to 9
- Light
- Full sun
- Flowers
- Late June to mid August
- Pets
- No toxicity recorded
- Job in a bed
- Drift
A bed built around Stokes' aster
The planner designed this bed around Stokes' aster when this page was made: a 12 × 6 ft (3.7 × 1.8 m) naturalistic planting in zone 6, full sun. It chose the other plants from the 966 that suit those conditions, and says below why Stokes' aster stands where it does.
The plants
- 1 Stokes' aster × 4, blue
- 2 Winter heath × 7, pink
- 3 Coral bells 'Firefly' × 8, red
- 4 Brown-eyed Susan × 3, yellow
- 5 Little bluestem × 3, blue-green leaves
- 6 Sea kale × 1, white
- 7 Ornamental onion 'Purple Sensation' × 5, purple
- 8 Tulip × 3, orange
Why this plant
- The only blue.
Why here
- In the middle. At 18 in it is seen over winter heath (10 in) in front of it.
- A step in the back row. Next to ornamental onion 'Purple Sensation' (2½ ft): no two neighbours there are the same height, so the back steps up and down like a skyline.
- 4 plants in one group. Massed, one kind reads as a single shape. Scattered, it would look spotty.
Why now
- In flower for 8 weeks. From late June to mid August.
- Part of the bed's peak. With coral bells 'Firefly' and sea kale in late June: 3 kinds at once. No week has more.
Planned as a naturalistic planting: low grasses and groundcovers, the matrix, make up 43% of the planted ground. For contrast, the bold leaves of sea kale sit beside the fine leaves of little bluestem. The most in flower at one time is 3 kinds, from late May.
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 Stokes' aster goes in a border
At 18 in it belongs at the front of a bed. In the planner's ten height classes it is short (12 to 18 in).
Its job: drift. Planted in a small group of three or five, and repeated further along in the other number.
A big, soft blue flower on a low plant, and unbothered by southern heat. It needs good drainage in winter more than anything else.
- Blue for the front of a summer border
- Cut flowers
- Hot, humid climates
What to plant with Stokes' aster
Plants recorded as good partners for it, and what each pairing does:
- Threadleaf coreopsis 'Moonbeam': purple against yellow, opposite each other on the colour wheel, if you choose those colours, in flower together for eight weeks.
- Daylily 'Stella de Oro': purple against yellow, opposite each other on the colour wheel, if you choose those colours, in flower together for eight weeks.
- Shasta daisy 'Snowcap': in flower together for eight weeks, from late June.
Questions about Stokes' aster
Does Stokes' aster need sun or shade?
Stokes' aster grows in full sun (6 or more hours of direct sun a day).
It wants ordinary well-drained soil, of average fertility, and a good soak in dry spells. Once settled in, it stands drought.
What zones does Stokes' aster grow in?
USDA zones 5 to 9. It is hardy to zone 5, which means it survives winter nights down to about −10 °F (−23 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does Stokes' aster flower in my zone?
In zone 5 it flowers late June to mid August. As a summer flower it moves about half a week for every zone: earlier where it is warmer.
| Zone 5 | Late June to mid August |
|---|---|
| Zone 6 | Late June to mid August |
| Zone 7 | Late June to early August |
| Zone 8 | Late June to early August |
| Zone 9 | Mid June to early August |
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 Stokes' aster be planted?
18 in (45 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 18 in (45 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many Stokes' aster plants do I need?
At 18 in apart, set out in staggered rows:
- 5 to fill 10 square feet (about 1 m²)
- 7 for a single row 10 ft (3 m) long
- 17 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as a group of three or five, with a second group further along in the other number.
In the bed above, the planner used four in one group.
Is Stokes' aster 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 Stokes' aster?
Mostly not. NC State lists it as resistant to deer and rabbits. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.
What flowers after Stokes' aster?
Stokes' aster is over by mid August. These start as it finishes and carry the same spot on, so it never goes flat:
- Lilyturf: from early August to mid September, 16 in tall.
- Garden chrysanthemum: from mid September to late October, 24 in tall.
- Sedum 'Autumn Joy': from mid August to mid October, 24 in tall.
What does Stokes' aster look like in winter?
Stokes' aster holds some of its leaves into winter, more in a mild year or a sheltered spot, and they look tired by March. Cut the old ones off as new growth starts.
Is Stokes' aster good for bees and butterflies?
Stokes' aster is visited by pollinators, bees and butterflies.
It is native to the United States.
In these guides
- Plants for wet soil and rain gardens
- Deer-resistant perennials for full sun
- Rabbit-resistant plants
- Drought-tolerant perennials for full sun
- Pet-safe plants for a sunny border
- Native perennials for pollinators
- Plants for butterflies
- Plants for bees
- Plants with blue flowers
- Plants for a white garden
Every fact on record
- Type
- Perennial
- Size
- 18 in (45 cm) tall, 18 in (45 cm) wide
- Plant
- 18 in (45 cm) apart
- Height class
- Short (12 to 18 in)
- Place in the bed
- Front
- Flowers
- Late June to mid August; daisies; blue, purple, white
- Leaves
- Medium texture, semi-evergreen; green
- Shape
- Mounding, clumping
- Hardy in
- USDA zones 5 to 9
- Light
- Full sun
- Soil
- Average, well-drained
- Water
- Moderate
- Feeding
- Light, in spring
- Family
- Asteraceae
- Comes from
- Southeastern United States
- Attracts
- Pollinators, bees, butterflies
- Stands up to
- Deer, rabbits, drought, wet soil
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.