Boltonia 'Snowbank'
Boltonia asteroides 'Snowbank' · Asteraceae
A cloud of small white daisies in early autumn on a tall, self-supporting plant with narrow, grey-green leaves.
- Size
- 4 ft tall, 3 ft wide
- Zones
- 3 to 9
- Light
- Full sun to part sun
- Flowers
- Early September to mid October
- Pets
- No toxicity recorded
- Job in a bed
- Drift
A bed built around boltonia 'Snowbank'
The planner designed this bed around boltonia 'Snowbank' 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 boltonia 'Snowbank' stands where it does.
The plants
- 1 Boltonia 'Snowbank' × 1, white
- 2 Bloody cranesbill 'Max Frei' × 8, pink
- 3 Winter heath × 8, purple
- 4 Astilbe 'Purple Candles' × 5, purple
- 5 Joe-Pye weed 'Baby Joe' × 3, pink
- 6 Palm sedge × 3, green leaves
- 7 Hyacinth × 5, blue
- 8 Star of Persia × 4, purple
Why this plant
- The only daisies. The others are open bowls, bells, plumes and others. Shape reads at a distance, where colours blur.
- The only white. White sits between stronger colours and calms them.
Why here
- Anchors a back corner. At 4 ft it is the tallest plant 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 joe-Pye weed 'Baby Joe' (2½ ft): no two neighbours there are the same height, so the back steps up and down like a skyline.
- One plant, alone. A feature plant is seen as an object, and needs clear ground around it.
Why now
- In flower for six weeks. From early September to mid October.
- Closes the season. For its last four weeks nothing else on the plan is in flower.
Planned as an English border: 6 of the 6 groups (100%) are drifts, longer along the bed than they are deep. The most in flower at one time is 3 kinds, from late July. Purple is the colour seen most, on 3 of the 7 kinds grown for their flowers.
The planner's own design check: 12 Excellent, 4 Good, 1 Satisfactory. 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 boltonia 'Snowbank' goes in a border
At 4 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.
White is scarce in autumn, and a mass of small white daisies makes the purples and golds around it look richer. This selection stands without staking in full sun; in shade it flops.
- White for the autumn border
- A partner for asters and grasses
- The back of a sunny bed
What to plant with boltonia 'Snowbank'
Plants recorded as good partners for it, and what each pairing does:
- New England aster: in flower together for six weeks, from early September.
- Switchgrass 'Shenandoah': its green leaves are a setting for the flowers, before and after.
- Joe Pye weed 'Gateway': in flower together for two weeks, from early September; bold leaves against its fine ones.
Questions about boltonia 'Snowbank'
Does boltonia 'Snowbank' need sun or shade?
Boltonia 'Snowbank' 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 ordinary well-drained soil, of average fertility, and a good soak in dry spells. It copes with soil that stays wet.
What zones does boltonia 'Snowbank' grow in?
USDA zones 3 to 9. It is hardy to zone 3, which means it survives winter nights down to about −30 °F (−34 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does boltonia 'Snowbank' 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 3 | Early September to mid October |
|---|---|
| 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 |
| Zone 9 | 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 boltonia 'Snowbank' be planted?
2½ ft (75 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 4 ft (120 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many boltonia 'Snowbank' plants do I need?
At 2½ ft apart, set out in staggered rows:
- 2 to fill 10 square feet (about 1 m²)
- 5 for a single row 10 ft (3 m) long
- 6 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 one in one group.
Is boltonia 'Snowbank' 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 boltonia 'Snowbank'?
Mostly not. NC State lists it as resistant to deer. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.
What flowers after boltonia 'Snowbank'?
Boltonia 'Snowbank' 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 boltonia 'Snowbank' look like in winter?
Boltonia 'Snowbank' 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 boltonia 'Snowbank' good for bees and butterflies?
Boltonia 'Snowbank' is visited by pollinators, butterflies and songbirds.
It is native to the United States and Canada (this is a named variety of the native plant).
In these guides
- Plants for wet soil and rain gardens
- Deer-resistant perennials for full sun
- Pet-safe plants for a sunny border
- Native perennials for pollinators
- Garden plants native to Canada
- Plants for butterflies
- Plants that feed garden birds
- Tall perennials and grasses for the back of a border
- Plants that flower in fall
- Plants for a white garden
- Silver and grey-leaved plants
Zone guides: Zone 3 · Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8 · Zone 9
Every fact on record
- Type
- Perennial
- Size
- 4 ft (120 cm) tall, 3 ft (90 cm) wide
- Plant
- 2½ ft (75 cm) apart
- Height class
- Moderately tall (3 to 4 ft)
- Place in the bed
- Back
- Flowers
- Early September to mid October; daisies; white
- Leaves
- Fine texture, herbaceous; grey-green
- Shape
- Upright, clumping
- Hardy in
- USDA zones 3 to 9
- Light
- Full sun, part sun
- Soil
- Average, well-drained
- Water
- Moderate
- Feeding
- None needed
- Family
- Asteraceae
- Comes from
- Eastern USA
- Attracts
- Pollinators, butterflies, songbirds
- Stands up to
- Deer, wet soil
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.