Bistort 'Superba'

Sun

Full sun where the soil stays moist; partial shade in warmer gardens.

Water

Keep the root zone consistently moist, especially during establishment and summer dry spells. Poorly suited to hot, dry gardens.

Soil

Moist, humus-rich soil, including moisture-retentive clay. Tolerates a broad pH range; avoid dry, thin soil and permanently submerged planting.

Height

2-3 ft (0.6-0.9 m)

Spread

2-3 ft (0.6-0.9 m), spreading farther over time

Flowers

Dense, pale to mid-pink spikes in late spring and early summer; occasional later flowers after cutting back.

Foliage

Broad, oblong green basal leaves with prominent veins, often forming a dense carpet; smaller leaves grow along the flowering stems. Dies back in winter.

Growth

Moderate to fast in moist, fertile soil

Care needed

Medium

• Pollinators
• Cold hardy
• Wildlife
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Fairly tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1 ft (0.3 m)

2. After 1 year

   1.6 ft (0.49 m)

3. After 2 years

   2.2 ft (0.68 m)

4. After 3 years

   2.5 ft (0.75 m)

   full size

About 2 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Native to

the US, Canada and the UK

In the garden

Spreads vigorously: plan to contain it.

Growth rate

Fast

• Water deeply during dry spells rather than allowing the root zone to dry out.
• Apply a thin layer of garden compost in spring; routine heavy feeding is unnecessary.
• Mulch to conserve moisture, keeping mulch clear of emerging shoots.
• Divide congested clumps in spring or early autumn.
• Lift unwanted rhizomes at the edge of the planting before they grow through neighbouring plants.

Pruning. Cut faded flower stems back to the basal leaves after the main flowering period; this may encourage a smaller second flush. Remove dead foliage in late autumn or before new growth starts in spring.

Early spring

Remove dead foliage and check for rhizomes spreading beyond the intended area.

Spring

Plant or divide clumps, water thoroughly and apply compost mulch.

Late spring

Check soil moisture as flower stems develop and water during dry weather.

Early summer

Cut spent flower stems down to the basal foliage.

Summer

Maintain moisture and remove unwanted shoots from neighbouring plants.

Early autumn

Divide or reduce established patches while the soil is moist and still warm.

• Plant in broad groups through a moist perennial border for repeated pink vertical accents.
• Use beside a pond or stream above the permanently flooded margin.
• Combine with moisture-loving grasses and perennials for a meadow-style planting.
• Use its broad foliage as spreading ground cover between larger plants in lightly shaded borders.

Garden styles it suits: Cottage garden, English country, New perennial (prairie), Bog garden, Wildlife garden and Blues and silvers.

Plant it with: Siberian iris, Globeflower, Astilbe, Meadowsweet, Tufted hair grass and Hosta.

Wildlife: The flowers provide nectar and pollen for bees and other visiting insects. Dense foliage offers shelter for small invertebrates.

• Dry soil can cause wilting, scorched leaves and early dormancy; water deeply, mulch and provide afternoon shade in warm sites.
• Rhizomes can crowd smaller neighbours; lift and remove surplus growth in spring or autumn.
• Slugs and snails may damage young leaves; inspect emerging shoots and use barriers or locally approved controls if damage is significant.

Not known to be toxic to people, cats, dogs or horses. The plant contains tannins, especially in the rhizomes; this is not a guarantee that large quantities are safe to eat, so discourage pets and livestock from feeding heavily on it.

Where it spreads. Can spread aggressively by rhizomes in moist garden soil, including gardens in the United Kingdom and cooler parts of North America. Keep it away from small, slow-growing plants and remove unwanted spread; this garden behaviour does not by itself mean it is officially listed as invasive.

• Red bistort (Bistorta amplexicaulis)

  Usually has taller, branched stems, narrower pointed leaves that clasp the stems, and slimmer flower spikes appearing mainly from summer into autumn.

• Lesser bistort (Bistorta affinis)

  Forms a much lower carpet of smaller leaves, with shorter flower stems; its pink spikes often deepen towards red as they age.

Bistorta comes from Latin words meaning 'twice twisted', referring to the twisted rhizome, while officinalis records the plant's historical medicinal use.

Propagation. Divide rhizomes in spring or early autumn, retaining healthy roots and growing buds on each piece. Division preserves 'Superba'; seedlings may not match the cultivar.

Accepted botanical name

Bistorta officinalis

In the US and Canada

Native in Alaska, Canada and the lower 48 states. Introduced in Canada and the lower 48 states.

Native range

Albania, Altay, Amur, Assam, Austria, Baltic States, Belarus, Belgium, Bulgaria, Buryatiya, Central European Rus and China North-Central.

Measured

Soil pH 6.5 to 7. Average height 16 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.