Bigleaf aster
Eurybia macrophylla · Asteraceae
Heart-shaped leaves as big as a hand make a weed-proof carpet in dry woodland; pale lilac daisies stand above them in late summer.
- Size
- 24 in tall, 3 ft wide
- Zones
- 3 to 8
- Light
- Part shade to shade
- Flowers
- Early August to mid September
- Pets
- No toxicity recorded
- Job in a bed
- Carpet
A bed built around bigleaf aster
The planner designed this bed around bigleaf aster when this page was made: a 12 × 6 ft (3.7 × 1.8 m) naturalistic planting in zone 6, part shade. It chose the other plants from the 513 that suit those conditions, and says below why bigleaf aster stands where it does.
The plants
- 1 Bigleaf aster × 3, lavender
- 2 Woodland strawberry × 8, white
- 3 Woodland phlox × 7, blue
- 4 Northern sea oats × 5, tan
- 5 Pieris 'Little Heath' × 1, variegated leaves
- 6 Tall astilbe 'Superba' × 3, purple
- 7 Grecian windflower × 5, pink
- 8 Hardy cyclamen × 10, pink
Why this plant
- The only bold leaves here. The rest are medium and fine. A change of leaf keeps plants distinct when nothing is in flower.
- Part of the matrix. The low fabric of grasses and groundcovers that the taller plants come up through.
- The only lavender.
Why here
- Under the taller plants. It runs back between them as living mulch: there its job is to cover the soil, not to be looked at.
- 3 plants in one group. Massed, one kind reads as a single shape. Scattered, it would look spotty.
- Bold leaf against fine. Pieris 'Little Heath' is beside it: the strongest contrast of leaf there is.
Why now
- In flower for 7 weeks. From early August to mid September.
- Part of the bed's peak. With woodland strawberry, northern sea oats and tall astilbe 'Superba' in early August: 4 kinds at once. No week has more.
Planned as a naturalistic planting: low grasses and groundcovers, the matrix, make up 58% of the planted ground. Northern sea oats and pieris 'Little Heath' carry the bed through winter. The bed is tied together by its repeats: two kinds come round again along it, woodland strawberry and woodland phlox.
The planner's own design check: 13 Excellent, 3 Good, 1 Satisfactory. It flags one thing to watch: Pieris 'Little Heath' is highly poisonous to people, dogs, cats and horses. Northern sea oats spreads aggressively.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where bigleaf aster goes in a border
At 24 in it belongs at the front of a bed. In the planner's ten height classes it is medium short (18 to 24 in).
Its job: carpet. A groundcover planted in threes and fives to cover the soil: along the front, and just behind it.
One of the few natives that covers ground in dry shade, even under maples. Grow it for the leaves and count the flowers, which are sparse in deep shade, as a bonus.
- Native groundcover for dry shade
- Under mature trees
- Woodland edges
What to plant with bigleaf aster
Plants recorded as good partners for it, and what each pairing does:
- Pennsylvania sedge: its green leaves are a setting for the flowers, before and after; fine leaves against its bold ones; low enough (8 in) to stand in front of it.
- Christmas fern: its dark green leaves are a setting for the flowers, before and after; medium leaves against its bold ones.
- White wood aster: in flower together for five weeks, from late August; medium leaves against its bold ones.
Questions about bigleaf aster
Does bigleaf aster need sun or shade?
Bigleaf aster grows in part shade (2 to 4 hours of sun, mostly in the morning) and shade (less than 2 hours of direct sun, or bright dappled light).
It wants ordinary well-drained soil, of average fertility, and little watering once settled.
What zones does bigleaf aster 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 bigleaf aster flower in my zone?
In zone 5 it flowers early August to mid September. As a summer flower it moves about half a week for every zone: earlier where it is warmer.
| Zone 3 | Mid August to mid September |
|---|---|
| Zone 4 | Mid August to mid September |
| Zone 5 | Early August to mid September |
| Zone 6 | Early August to mid September |
| Zone 7 | Early August to mid September |
| Zone 8 | Early August to mid September |
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 bigleaf aster be planted?
24 in (60 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 3 ft (90 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 bigleaf aster 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 threes and fives, along the front and just behind it.
In the bed above, the planner used three in one group.
Is bigleaf 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 bigleaf aster?
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.
Will bigleaf aster spread?
It spreads sideways, by runners or roots; the risk of it taking over is moderate. Spreads steadily by underground stems into a broad colony. Edge it where it meets smaller plants.
What flowers after bigleaf aster?
Bigleaf aster is over by mid September. These start as it finishes and carry the same spot on, so it never goes flat:
- Toad lily: from mid September to mid October, 2½ ft tall.
- Blue wood aster: from mid September to mid October, 3 ft tall.
- White snakeroot 'Chocolate': from mid September to mid October, 3½ ft tall.
What does bigleaf aster look like in winter?
Bigleaf aster 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 bigleaf aster good for bees and butterflies?
Bigleaf aster is visited by pollinators, bees, butterflies and songbirds.
It is native to the United States and Canada.
More Eurybia
- White wood aster Eurybia divaricata
In these guides
- Pet-safe plants for shade
- Native perennials for pollinators
- Native plants for shade
- Garden plants native to Canada
- Plants for butterflies
- Plants for bees
- Plants that feed garden birds
- Groundcover plants
Zone guides: Zone 3 · Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8
Every fact on record
- Type
- Perennial (groundcover)
- Size
- 24 in (60 cm) tall, 3 ft (90 cm) wide
- Plant
- 24 in (60 cm) apart
- Height class
- Medium short (18 to 24 in)
- Place in the bed
- Front
- Flowers
- Early August to mid September; daisies; lavender, white
- Leaves
- Bold texture, herbaceous; green
- Shape
- Mat-forming, spreading
- Hardy in
- USDA zones 3 to 8
- Light
- Part shade, shade
- Soil
- Average, well-drained
- Water
- Low
- Feeding
- None needed
- Family
- Asteraceae
- Comes from
- Eastern and Central North America
- Attracts
- Pollinators, bees, butterflies, songbirds
Checked against NC State Extension and VASCAN (plants of Canada). 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.