Smooth aster 'Bluebird'
Symphyotrichum laeve 'Bluebird' · Asteraceae
Clouds of violet-blue, yellow-centred daisies in early autumn on a vase-shaped plant with smooth, blue-green leaves that stay clean all season.
- Size
- 3½ ft tall, 24 in wide
- Zones
- 4 to 8
- Light
- Full sun
- Flowers
- Early September to mid October
- Pets
- No toxicity recorded
- Job in a bed
- Drift
A bed built around smooth aster 'Bluebird'
The planner designed this bed around smooth aster 'Bluebird' 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 smooth aster 'Bluebird' stands where it does.
The plants
- 1 Smooth aster 'Bluebird' × 3, blue
- 2 Bloody cranesbill 'Max Frei' × 7, pink
- 3 Winter heath × 8, white
- 4 Brown-eyed Susan × 5, yellow
- 5 Silver sage × 1, silver leaves
- 6 Coneflower 'PowWow Wild Berry' × 3, pink
- 7 Ornamental onion 'Purple Sensation' × 3, purple
- 8 Darwin hybrid tulip × 8, red
Why this plant
- The only blue.
Why here
- Anchors a back corner. At 3½ ft it is among the tallest plants here, and the tallest close the ends of the bed, where they stand in front of nothing.
- A step in the back row. Next to coneflower 'PowWow Wild Berry' (22 in): no two neighbours there are the same height, so the back steps up and down like a skyline.
- 3 plants in one group. Massed, one kind reads as a single shape. Scattered, it would look spotty.
Why now
- In flower for six weeks. From early September to mid October.
- Closes the season. In its last week nothing else on the plan is in flower.
Planned as an English border: 5 of the 6 groups (83%) are drifts, longer along the bed than they are deep. Heights step up from about 10 in at the front to 3 ft at the back. In winter there is still winter heath to look at.
The planner's own design check: 14 Excellent, 3 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 smooth aster 'Bluebird' goes in a border
At 3½ ft it belongs at the back of a bed. In the planner's ten height classes it is moderately tall (3 to 4 ft).
Its job: drift. Planted in a small group of three or five, and repeated further along in the other number.
The leaves resist mildew and do not go brown at the base, the usual faults of tall asters. It consistently comes top in trials. Good with goldenrods.
- A tall aster that stays healthy
- Prairie planting with grasses
- Autumn pollinators
What to plant with smooth aster 'Bluebird'
Plants recorded as good partners for it, and what each pairing does:
- Goldenrod 'Fireworks': blue against yellow, opposite each other on the colour wheel, in flower together for six weeks.
- Little bluestem: its blue-green leaves are a setting for the flowers, before and after.
- Showy goldenrod: blue against yellow, opposite each other on the colour wheel, in flower together for six weeks.
Questions about smooth aster 'Bluebird'
Does smooth aster 'Bluebird' need sun or shade?
Smooth aster 'Bluebird' grows in full sun (6 or more hours of direct sun a day).
It wants ordinary well-drained soil, of average fertility, and little watering once settled. Once settled in, it stands drought.
What zones does smooth aster 'Bluebird' 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 smooth aster 'Bluebird' flower in my zone?
In zone 5 it flowers early September to mid October. As an autumn flower it keeps much the same dates in every zone: it answers to shortening days and cool nights more than to the warmth of spring.
| Zone 4 | Early September to mid October |
|---|---|
| Zone 5 | Early September to mid October |
| Zone 6 | Early September to mid October |
| Zone 7 | Early September to mid October |
| Zone 8 | Early September to mid October |
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 smooth aster 'Bluebird' be planted?
24 in (60 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 3½ ft (100 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many smooth aster 'Bluebird' plants do I need?
At 24 in apart, set out in staggered rows:
- 3 to fill 10 square feet (about 1 m²)
- 6 for a single row 10 ft (3 m) long
- 10 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 three in one group.
Is smooth aster 'Bluebird' 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 smooth aster 'Bluebird'?
They may. NC State does not list it as resistant to deer or rabbits. Where they visit, protect it, or plant it among ones they avoid.
What flowers after smooth aster 'Bluebird'?
Smooth aster 'Bluebird' is over by mid October. These start as it finishes and carry the same spot on, so it never goes flat:
- Tatarian aster 'Jindai': from early October to early November, 4 ft tall.
- Japanese onion 'Ozawa': from early October to early November, 10 in tall, to stand in front of it and cover its fading stems.
- Bodnant viburnum 'Dawn': from early November to late December, 10 ft tall.
What does smooth aster 'Bluebird' look like in winter?
Smooth aster 'Bluebird' dies down, but leave the stems standing: the seed heads stand through the winter, and songbirds eat the seed. Cut them down in early spring, before the new shoots come.
Is smooth aster 'Bluebird' good for bees and butterflies?
Smooth aster 'Bluebird' is visited by pollinators, bees, specialist bees, butterflies, beneficial insects and songbirds.
It is a host plant: the caterpillars of pearl crescent feed on its leaves. A butterfly can only lay its eggs on its host plants, so these do more for it than any nectar flower.
It is native to the United States and Canada (this is a named variety of the native plant).
More Symphyotrichum
- Aromatic aster 'October Skies' Symphyotrichum oblongifolium 'October Skies'
- Aromatic aster 'Raydon's Favorite' Symphyotrichum oblongifolium 'Raydon's Favorite'
- Aster 'Wood's Purple' Symphyotrichum 'Wood's Purple'
- Blue wood aster Symphyotrichum cordifolium
- Calico aster 'Lady in Black' Symphyotrichum lateriflorum 'Lady in Black'
- Heath aster 'Snow Flurry' Symphyotrichum ericoides 'Snow Flurry'
- New England aster Symphyotrichum novae-angliae
- New England aster 'Alma Pötschke' Symphyotrichum novae-angliae 'Andenken an Alma Pötschke'
- New England aster 'Purple Dome' Symphyotrichum novae-angliae 'Purple Dome'
- New York aster Symphyotrichum novi-belgii
In these guides
- Drought-tolerant perennials for full sun
- Pet-safe plants for a sunny border
- Native perennials for pollinators
- Garden plants native to Canada
- Plants for butterflies
- Plants for bees
- Plants that feed garden birds
- Plants that flower in fall
- Plants with blue flowers
- Host plants for the pearl crescent
Every fact on record
- Type
- Perennial
- Size
- 3½ ft (100 cm) tall, 24 in (60 cm) wide
- Plant
- 24 in (60 cm) apart
- Height class
- Moderately tall (3 to 4 ft)
- Place in the bed
- Back
- Flowers
- Early September to mid October; daisies; blue
- Leaves
- Medium texture, herbaceous; blue-green
- Shape
- Upright, clumping
- Hardy in
- USDA zones 4 to 8
- Light
- Full sun
- Soil
- Average, well-drained
- Water
- Low
- Feeding
- None needed
- Family
- Asteraceae
- Comes from
- Much of North America and parts of Mexico
- Attracts
- Pollinators, bees, specialist bees, butterflies, beneficial insects, songbirds
- Host plant for
- Pearl crescent
- Stands up to
- Drought
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.