Persicaria mollis
Soft-leaved knotweed
Also known as Polygonum molle, Polygonum paniculatum
- Height × spread
- 2.5m × 2m
- Position
- Full sun
- Hardiness
- Cold to -15C (RHS H5)
- Flowers
- Summer
Availability
Please ask in store about availability
Many plants are seasonal. Call 01234 567890 to check current stock.
About this plant
Not for the faint-hearted, this towering plant stands upright with sturdy red-brown stalks that carry good-sized rich green lance shaped leaves, with softly impressed forward pointing veins, and downy to the touch. The flowers form frothy panicles (not unlike those of astilbe). There are masses of tiny white flowers, sometimes touched with pink and on pink tinted stems. They develop into a huge inflorescence that sits at the top like a giant fat ice-cream cone. A major feature from mid to late summer. They carry a slight fragrance. It might be advisable not to let this self-seed if you have a small garden!
- Flower colour
- White
- Foliage colour
- Green
- Fruit colour
- Pink
- Variegated
- No
- Scent
- Yes, slight
- Shape
- Cube
- Height
- 2.5m
- Spread
- 2m
- Season of interest
- Summer
- Flowers in
- Summer
- Evergreen
- Deciduous
- Garden style
- Prairie garden
- Sun or shade
- Likes full sun, likes part shade, tolerates light shade
- Soil type
- Chalk, Loam (normal)
- Soil pH
- All types
- Drainage
- Moisture retentive soil, Well drained soil
- Hardiness
- Cold to -15C (RHS H5)
- Borders & containers
- Borders
- Use for
- Architectural, Sensory garden (tactile)
- Maintenance
- Easycare – low/no maintenance
- Hazards
- No
Spring
Spring - late · Outdoors
Feed with slow release fertiliser
Apply a general purpose slow release fertiliser, spreading it around the root area of the plant as it is coming into growth. (Or apply a liquid feed at regular intervals throughout the growing season.)
This is a simple way to provide a nutrient boost as a single annual procedure.
Spring-Autumn · Outdoors
Water to keep the soil moist
For best results, this plant needs soil that is always moist. Water deeply and regularly as soon as soil appears dry. Even for established plants in the ground, a dry week can cause problems with some soils. Check plants in pots more often, especially in hot weather. Or install an automatic irrigation system which will do the hard work for you, even when you are away on holiday.
Without regular watering some plants never fully regain their beauty.
Spring - early-mid · Planting
Divide when too large
The plant can be divided if it becomes too large or another plant is required. This may involve physically dividing the clump in two, removing offsets or small bulbs or dividing rhizomes. The new plants can be grown in pots or planted in the ground.
Found in
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