White snakeroot 'Chocolate'
Ageratina altissima 'Chocolate' · Asteraceae (Compositae) - Aster or Sunflower Family
Chocolate-purple leaves on dark stems through spring and summer, then clouds of fluffy white flowers in early autumn, when the leaves turn greener.
- Size
- 3½ ft tall, 2½ ft wide
- Zones
- 4 to 8
- Light
- Full sun to part shade
- Flowers
- Mid September to mid October
- Pets
- Toxic to people and horses
- Job in a bed
- Drift
A bed built around white snakeroot 'Chocolate'
The planner designed this bed around white snakeroot 'Chocolate' when this page was made: a 12 × 6 ft (3.7 × 1.8 m) cottage garden in zone 6, part sun. It chose the other plants from the 708 that suit those conditions, and says below why white snakeroot 'Chocolate' stands where it does.
The plants
- 1 White snakeroot 'Chocolate' × 3, white
- 2 Blue star creeper × 8, blue
- 3 Mouse-ear coreopsis 'Nana' × 11, yellow
- 4 Joe Pye weed 'Little Joe' × 4, pink
- 5 Globe arborvitae 'Danica' × 1, green leaves
- 6 Golden ragwort × 3, yellow
- 7 Snowdrop × 8, white
- 8 Camassia × 4, blue
Why this plant
- The only dense clusters. The others are daisies, flat plates, bells and others. Shape reads at a distance, where colours blur.
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 Joe Pye weed 'Little Joe' (4 ft): 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 five weeks. From mid September to mid October.
- Closes the season. In all that time nothing else on the plan is in flower.
Planned as a cottage garden: 30 of the 30 plants (100%), bulbs aside, stand alone or in groups of no more than five, small enough for the kinds to mingle. Cool colours (blue and pink) with yellow as the warm note, and white to calm things between them. Mouse-ear coreopsis 'Nana' repeats along the bed to tie it together.
The planner's own design check: 12 Excellent, 5 Good.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where white snakeroot 'Chocolate' 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.
One of the few dark-leaved plants that tolerates dry shade. The white autumn flowers against the dark leaves are a bonus. Remove the spent flowers, because it seeds about and the seedlings come up green.
- Dark foliage for part shade
- Late white flowers under trees
- Native woodland-edge planting
What to plant with white snakeroot 'Chocolate'
Plants recorded as good partners for it, and what each pairing does:
- Japanese anemone: in flower together for four weeks, from mid September; happy in the same moist soil.
- Hosta: its green leaves are a setting for the flowers, before and after; bold leaves against its medium ones; low enough (18 in) to stand in front of it.
- Christmas fern: its dark green leaves are a setting for the flowers, before and after; low enough (20 in) to stand in front of it.
Questions about white snakeroot 'Chocolate'
Does white snakeroot 'Chocolate' need sun or shade?
White snakeroot 'Chocolate' grows in full sun (6 or more hours of direct sun a day), part sun (4 to 6 hours of sun, including some afternoon sun) and part shade (2 to 4 hours of sun, mostly in the morning).
It wants soil that stays evenly moist, of average fertility, and a good soak in dry spells.
What zones does white snakeroot 'Chocolate' 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 white snakeroot 'Chocolate' flower in my zone?
In zone 5 it flowers mid 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 | Mid September to mid October |
|---|---|
| Zone 5 | Mid September to mid October |
| Zone 6 | Mid September to mid October |
| Zone 7 | Mid September to mid October |
| Zone 8 | Mid 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 white snakeroot 'Chocolate' 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 2½ ft (75 cm), so a group knits into one patch.
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 white snakeroot 'Chocolate' 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 white snakeroot 'Chocolate' poisonous?
Yes: severe toxicity to people and horses. All parts are highly poisonous if eaten, especially to horses and other grazing animals.
Rated from NC State Extension and the ASPCA. Where references disagree, the more cautious rating is used.
Do deer eat white snakeroot 'Chocolate'?
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.
Will white snakeroot 'Chocolate' spread?
It seeds itself about; the risk of it taking over is moderate. Self-seeds freely. Remove the spent flowers to limit seedlings.
What flowers after white snakeroot 'Chocolate'?
White snakeroot 'Chocolate' 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 white snakeroot 'Chocolate' look like in winter?
White snakeroot 'Chocolate' 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 white snakeroot 'Chocolate' good for bees and butterflies?
White snakeroot 'Chocolate' 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).
More Ageratina
- White snakeroot Ageratina altissima
In these guides
- Deer-resistant plants for shade
- Deer-resistant perennials for full sun
- Native perennials for pollinators
- Native plants for shade
- Garden plants native to Canada
- Plants for butterflies
- Plants that feed garden birds
- Plants that flower in fall
- Plants for a white garden
- Plants with purple and burgundy leaves
Every fact on record
- Type
- Perennial
- Size
- 3½ ft (100 cm) tall, 2½ ft (75 cm) wide
- Plant
- 24 in (60 cm) apart
- Height class
- Moderately tall (3 to 4 ft)
- Place in the bed
- Back
- Flowers
- Mid September to mid October; dense clusters; white
- Leaves
- Medium texture, herbaceous; burgundy
- Shape
- Upright, self-seeding
- Hardy in
- USDA zones 4 to 8
- Light
- Full sun, part sun, part shade
- Soil
- Average, evenly moist
- Water
- Moderate
- Feeding
- None needed
- Family
- Asteraceae (Compositae) - Aster or Sunflower Family
- Comes from
- Native to woodlands in Eastern United States
- Attracts
- Pollinators, butterflies, songbirds
- Stands up to
- Deer
Checked against NC State Extension, ASPCA poison lists 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.