Persicaria filiformis 'Ballet'

RHS Plant Profile

knotweed 'Ballet'

RHS / Joanna Kossak

Synonyms

Persicaria virginiana var. filiformis 'Ballet'

Herbaceous Perennial

A clump-forming, deciduous herbaceous perennial with ovate pale green leaves and upright spikes of small, graceful wispy white flowers which appear from summer through until the autumn

Position

Full sun, Partial shade

Soil Types

Chalk, Clay, Loam, Sand

Max Height

0.5-1 metres

Max Spread

0.5-1 metres

Size

Time to Maturity: 2–5 years
Max Spread: 0.5-1 metres
Max Height: 0.5-1 metres

Growing Conditions

Chalk Clay Loam Sand

Moisture: Moist but well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun Partial shade

Aspect: East–facing or North–facing or South–facing or West–facing
Exposure: Exposed or Sheltered
Hardiness

Hardiness Ratings

All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets

H1A: under glass all year (>15C)
H1B: can be grown outside in the summer (10 - 15)
H1C: can be grown outside in the summer (5 - 10)
H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
H4: hardy through most of the UK (-10 to -5)
H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
H6: hardy in all of UK and northern Europe (-20 to -15)
H7: hardy in the severest European continental climates (< -20): H6

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Polygonaceae
Native to GB/Ireland: No
Foliage: Deciduous
Habit: Clump forming
Genus: Persicaria can be annuals, herbaceous or evergreen perennials or sub-shrubs with simple leaves and small bell-shaped white or pink flowers in long-lasting spikes or panicles
Name Status: Accepted

How to Grow

Cultivation

Grow in moisture-retentive but well-drained soil in full sun or partial shade See https://www.rhs.org.uk/plants/trials-awards for further information about RHS plant trials and awards

Propagation

Propagate by division in spring or autumn

Suggested planting locations and garden types

City and courtyard gardens
Cottage and informal garden
Flower borders and beds

Pruning

Cut back old, flowered stems to the ground in autumn

Pests

Generally pest-free but may be susceptible to slugs and snails

Diseases

Generally disease-free