Bistort 'Superba'
Persicaria bistorta 'Superba' ·
Soft pink, bottle-brush spikes stand well above dense clumps of large, dock-like leaves in late spring and early summer. It needs moist soil.
- Size
- 2½ ft tall, 3 ft wide
- Zones
- 4 to 8
- Light
- Full sun to part sun
- Flowers
- Late May to late June
- Pets
- Not checked
- Job in a bed
- Drift
A bed built around bistort 'Superba'
The planner designed this bed around bistort 'Superba' 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 bistort 'Superba' stands where it does.
The plants
- 1 Bistort 'Superba' × 3, pink
- 2 Winter heath × 5, white
- 3 Leadwort × 8, blue
- 4 Italian bugloss 'Dropmore' × 3, blue
- 5 Silver sage × 1, silver leaves
- 6 Eastern bee balm × 5, pink
- 7 Crown imperial × 3, yellow
- 8 Meadow saffron × 3, pink
Why this plant
- The only spires. The others are bells, dense clusters, airy sprays and others. Shape reads at a distance, where colours blur.
Why here
- At the back. At 2½ ft it is seen over eastern bee balm (20 in) in front of it, and has nothing behind it to hide.
- A step in the back row. Next to crown imperial (3½ ft) and Italian bugloss 'Dropmore' (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 six weeks. From late May to late June.
- Part of the bed's peak. With Italian bugloss 'Dropmore' and eastern bee balm in late May: 3 kinds at once. No week has more.
Planned as a cottage garden: 25 of the 25 plants (100%), bulbs aside, stand alone or in groups of no more than five, small enough for the kinds to mingle. Pink runs through the planting: 3 of the 7 kinds grown for their flowers have it. The bold leaves of bistort 'Superba' are set against the fine leaves of winter heath, the kind of contrast that keeps a bed from blurring.
The planner's own design check: 8 Excellent, 9 Good.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where bistort 'Superba' goes in a border
At 2½ ft it belongs in the middle of a bed. In the planner's ten height classes it is medium (24 in to 2½ ft).
Its job: drift. Planted in a small group of three or five, and repeated further along in the other number.
A flower shape that is rare in May and June. In moist soil it makes a wide, weed-proof mat; in dry soil it sulks. Lovely with Siberian iris.
- Pink spires for moist soil
- Beside water
- Weed-suppressing groundcover
What to plant with bistort 'Superba'
Plants recorded as good partners for it, and what each pairing does:
- Siberian iris: in flower together for four weeks, from late May; fine leaves against its bold ones; happy in the same moist soil.
- Lady's mantle: in flower together for five weeks, from late May; medium leaves against its bold ones; a low mound at the foot of its spires.
- Globeflower: in flower together for five weeks, from late May; medium leaves against its bold ones; happy in the same moist soil.
Questions about bistort 'Superba'
Does bistort 'Superba' need sun or shade?
Bistort 'Superba' 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 soil that stays evenly moist, rich in organic matter, and plenty of water.
What zones does bistort 'Superba' 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 bistort 'Superba' flower in my zone?
In zone 5 it flowers late May to late June. As a spring flower it moves about a week for every zone: earlier where it is warmer, later where it is colder.
| Zone 4 | Late May to early July |
|---|---|
| Zone 5 | Late May to late June |
| Zone 6 | Mid May to late June |
| Zone 7 | Early May to late June |
| Zone 8 | Early May to late June |
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 bistort 'Superba' 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 2½ ft (75 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many bistort 'Superba' 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 there a native plant like bistort 'Superba'?
Bistort 'Superba' is not native to North America. These North American natives come closest to doing its job:
- Bowman's root: the same job in a bed and the same flowering time; 6 in taller, white, not pink.
- Southern blue flag: the same job in a bed and the same flowering time; 4 in narrower, blue, not pink.
- Wild geranium: the same job in a bed and the same colour; 10 in shorter, 6 in narrower.
Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.
Will bistort 'Superba' spread?
It spreads sideways, by runners or roots; the risk of it taking over is moderate. Spreads by underground runners and can crowd its neighbours. Dig out the edges or divide every 2 to 3 years.
What flowers after bistort 'Superba'?
Bistort 'Superba' is over by late June. These start as it finishes and carry the same spot on, so it never goes flat:
- Black-eyed Susan: from mid July to mid September, 24 in tall.
- Butterfly weed: from late June to early August, 24 in tall.
- Daylily: from late June to early August, 2½ ft tall.
What does bistort 'Superba' look like in winter?
Bistort 'Superba' 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.
More Persicaria
- Giant fleeceflower Persicaria polymorpha
- Himalayan fleeceflower 'Darjeeling Red' Persicaria affinis 'Darjeeling Red'
- Mountain fleece 'Firetail' Persicaria amplexicaulis 'Firetail'
- Mountain fleece 'Golden Arrow' Persicaria amplexicaulis 'Golden Arrow'
In these guides
Every fact on record
- Type
- Perennial
- Size
- 2½ ft (75 cm) tall, 3 ft (90 cm) wide
- Plant
- 24 in (60 cm) apart
- Height class
- Medium (24 in to 2½ ft)
- Place in the bed
- Middle
- Flowers
- Late May to late June; upright spires; pink
- Leaves
- Bold texture, herbaceous; green
- Shape
- Mounding, spreading
- Hardy in
- USDA zones 4 to 8
- Light
- Full sun, part sun
- Soil
- Rich, evenly moist
- Water
- High
- Feeding
- None needed
Checked against 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.