Culver's root
Veronicastrum virginicum · Plantaginaceae
Slender white or pale lilac spires branch like a candelabra at the top of tall, straight stems, with leaves in neat whorls all the way up.
- Size
- 5 ft tall, 2½ ft wide
- Zones
- 3 to 8
- Light
- Full sun
- Flowers
- Early July to mid August
- Pets
- No toxicity recorded
- Job in a bed
- Accent
A bed built around Culver's root
The planner designed this bed around Culver's root when this page was made: a 12 × 6 ft (3.7 × 1.8 m) cottage garden in zone 6, full sun. It chose the other plants from the 966 that suit those conditions, and says below why Culver's root stands where it does.
The plants
- 1 Culver's root × 3, white
- 2 Mouse-ear coreopsis 'Nana' × 18, yellow
- 3 Winter heath × 5, pink
- 4 Korean feather reed grass × 1, pink
- 5 Rose turtlehead × 8, pink
- 6 Tulip 'Apeldoorn' × 7, red
- 7 Daffodil × 5, yellow
Why this plant
- The only white. White sits between stronger colours and calms them.
Why here
- Anchors a back corner. At 5 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 rose turtlehead (2½ ft): no two neighbours there are the same height, so the back steps up and down like a skyline.
- 3 plants in one clump. A single spire is too slight to hold a place alone, so here the accent is a clump.
Why now
- In flower for 7 weeks. From early July to mid August.
- Fills a gap. For six of those weeks nothing else on the plan is in flower.
Planned as a cottage garden: 26 of the 35 plants (74%), bulbs aside, stand alone or in groups of no more than five, small enough for the kinds to mingle. The most in flower at one time is 3 kinds, in early May. Pink is the colour seen most, on 3 of the 7 kinds grown for their flowers.
The planner's own design check: 8 Excellent, 8 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 Culver's root goes in a border
At 5 ft it belongs at the back of a bed. In the planner's ten height classes it is tall (4 to 5 ft).
Its job: accent. An upright plant used singly, like a punctuation mark, and repeated at intervals to give the bed rhythm.
The most architectural native perennial: strict, upright lines from top to bottom, and a silhouette that lasts into winter. It takes two or three years to reach full size.
- Elegant verticals for the back of a border
- Naturalistic and prairie planting
- Moist soil
What to plant with Culver's root
Plants recorded as good partners for it, and what each pairing does:
- Joe Pye weed 'Gateway': in flower together for four weeks, from late July; bold leaves against its medium ones; happy in the same moist soil.
- Queen of the prairie: in flower together for four weeks, from early July; bold leaves against its medium ones; happy in the same moist soil.
- Switchgrass 'Shenandoah': its green leaves are a setting for the flowers, before and after.
Questions about Culver's root
Does Culver's root need sun or shade?
Culver's root grows in full sun (6 or more hours of direct sun a day).
It wants soil that stays evenly moist, rich in organic matter, and a good soak in dry spells. It copes with soil that stays wet.
What zones does Culver's root 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 Culver's root flower in my zone?
In zone 5 it flowers early July to mid August. As a summer flower it moves about half a week for every zone: earlier where it is warmer.
| Zone 3 | Mid July to late August |
|---|---|
| Zone 4 | Mid July to late August |
| Zone 5 | Early July to mid August |
| Zone 6 | Early July to mid August |
| Zone 7 | Late June to early August |
| Zone 8 | Late 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 Culver's root 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 5 ft (150 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many Culver's root 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 one at a time, repeated along the bed at intervals; a slender one reads better as a clump of three.
In the bed above, the planner used three in one group.
Is Culver's root 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 Culver's root?
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 Culver's root?
Culver's root is over by mid August. These start as it finishes and carry the same spot on, so it never goes flat:
- Garden chrysanthemum: from mid September to late October, 24 in tall, to stand in front of it and cover its fading stems.
- Little bluestem 'Standing Ovation': from early August to mid September, 3½ ft tall, to stand in front of it and cover its fading stems.
- Lilyturf: from early August to mid September, 16 in tall, to stand in front of it and cover its fading stems.
What does Culver's root look like in winter?
Culver's root dies down to the ground and there is nothing to see until spring. The old stems can be cut in autumn, or left until spring as shelter for overwintering insects.
Is Culver's root good for bees and butterflies?
Culver's root is visited by pollinators, specialist bees, butterflies and beneficial insects.
It is native to the United States and Canada.
More Veronicastrum
- Culver's root 'Fascination' Veronicastrum virginicum 'Fascination'
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 for bees
- Tall perennials and grasses for the back of a border
- Plants with spires: vertical accents
- Plants for a white garden
Zone guides: Zone 3 · Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8
Every fact on record
- Type
- Perennial
- Size
- 5 ft (150 cm) tall, 2½ ft (75 cm) wide
- Plant
- 24 in (60 cm) apart
- Height class
- Tall (4 to 5 ft)
- Place in the bed
- Back
- Flowers
- Early July to mid August; upright spires; white, lavender
- Leaves
- Medium texture, herbaceous; dark green
- Shape
- Upright, clumping
- Hardy in
- USDA zones 3 to 8
- Light
- Full sun
- Soil
- Rich, evenly moist
- Water
- Moderate
- Feeding
- Light, in spring
- Family
- Plantaginaceae
- Comes from
- North America
- Attracts
- Pollinators, specialist bees, butterflies, beneficial insects
- Stands up to
- Deer, 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.