Overview
Polygonum amplexicaule 'Firetail' is a mat-forming, clump-forming or tall and upright perennial in the genus Polygonum, part of the Polygonaceae family, with deciduous; simple, lance-shaped to heart-shaped, often marked or autumn-tinted foliage. It typically grows around 1.2 metres tall. Polygonum amplexicaule 'Firetail' grows best in full sun to partial shade, and tolerates almost any soil and including heavy clay soils and acid and neutral or alkaline pH. Its UK hardiness is rated H5-H7. It is native to China, Himalayas and Pakistan.
About
Polygonum amplexicaule 'Firetail' is a perennial knotweed that can form mats, clumps or grow tall and upright to about 1.2 metres. Its deciduous leaves are simple, lance- to heart-shaped and are often marked or take on autumn tint. It prefers moist conditions and tolerates a very wide range of soils, including heavy clay, but dislikes drought. Flowering occurs July to September.
Wikipedia contributors, CC BY-SA 4.0 — Bistorta amplexicaulis
About the genus
Polygonum is a genus of about 130 species of flowering plants in the buckwheat and knotweed family Polygonaceae. Common names include knotweed and knotgrass. In the Middle English glossary of herbs Alphita, it was known as ars-smerte.
Wikipedia contributors, "Polygonum", CC BY-SA 4.0 — Polygonum
In the garden
Polygonum amplexicaule 'Firetail' is a member of the Polygonaceae from China, the Himalayas and Pakistan. It presents as mat-forming or clump-forming plants, or in some situations produces erect stems up to around 1.2 metres, with deciduous, lance- to heart-shaped leaves that may be marked or autumn-tinted. Give it full sun to partial shade on any aspect; the species adapts to acid, neutral or alkaline soils and will grow in almost any soil type, including heavy clay. It prefers moist ground and most plants tolerate damp conditions but will not perform where drought is persistent. Exposure is not critical — it will establish in both sheltered and more exposed sites. In UK hardiness terms the range H5–H7 means it is hardy through typical UK winters, from hardy to fully hardy. Use 'Firetail' where soil remains reliably moist: it suits the middle to rear of mixed perennial borders or larger beds where stems can reach their height without being shaded out. Flowers appear in summer, from July to September, carried on the taller stems rather than within the leaf canopy.
Growing conditions
Best soil and position for Polygonum
- Sunlight
- Full sun to partial shade
- Soil type
- Almost any soil, including heavy clay
- Soil pH
- Acid, neutral or alkaline
- Soil moisture
- Moist; most tolerate damp ground and dislike drought
- Aspect
- Any
- Exposure
- Exposed or sheltered
- UK hardiness
- H5-H7
Plant details
Polygonum amplexicaule 'Firetail' size, habit and characteristics
- Plant type
- Perennial
- Habit
- Mat-forming, clump-forming or tall and upright
- Foliage
- Deciduous; simple, lance-shaped to heart-shaped, often marked or autumn-tinted
- Height
- 1.2 metres
- Native to
- China, Himalayas, Pakistan
Care notes
Pruning and caring for Polygonum amplexicaule 'Firetail'
- Cultivation
- Undemanding to the point of needing restraint rather than encouragement. Give reliable moisture and they flower for months. Vigour is the main consideration: check the spread of any given species before planting, since the running kinds colonise fast and are difficult to remove once established, while the clump-forming ones are well behaved. Note that most garden knotweeds are now classified under Persicaria.
- Pruning
- Cut back to the base in late autumn, or leave the dried spikes standing for winter interest and clear in early spring. Shear mat-forming kinds after the first flush to tidy them.
- Propagation
- Divide in spring or autumn - most divide very easily. Basal cuttings root readily in spring.
- Pest resistance
- Slugs graze new growth; otherwise notably trouble-free.
- Disease resistance
- Healthy and robust. Powdery mildew occurs on plants that dry out.
Frequently asked questions
How do I grow Polygonum amplexicaule 'Firetail'?
Undemanding to the point of needing restraint rather than encouragement. Give reliable moisture and they flower for months. Vigour is the main consideration: check the spread of any given species before planting, since the running kinds colonise fast and are difficult to remove once established, while the clump-forming ones are well behaved. Note that most garden knotweeds are now classified under Persicaria.
Where is the best place to plant Polygonum amplexicaule 'Firetail'?
Polygonum amplexicaule 'Firetail' prefers full sun to partial shade. It suits exposed or sheltered positions.
What soil does Polygonum amplexicaule 'Firetail' need?
Polygonum amplexicaule 'Firetail' grows best in almost any soil and including heavy clay soil. It prefers acid and neutral or alkaline soil. Aim for soil that stays moist; most tolerate damp ground and dislike drought.
How do I prune Polygonum amplexicaule 'Firetail'?
Cut back to the base in late autumn, or leave the dried spikes standing for winter interest and clear in early spring. Shear mat-forming kinds after the first flush to tidy them.
How big does Polygonum amplexicaule 'Firetail' grow?
Polygonum amplexicaule 'Firetail' reaches a height of 1.2 metres.
Is Polygonum amplexicaule 'Firetail' hardy in the UK?
Polygonum amplexicaule 'Firetail' has an RHS hardiness rating of H5, meaning it is hardy in most of the UK, tolerating -15 to -10°C.
How do I propagate Polygonum amplexicaule 'Firetail'?
Divide in spring or autumn - most divide very easily. Basal cuttings root readily in spring.
More in the Polygonum genus
- Polygonum affineHimalayan bistort, fleece flower
- Polygonum affine 'Superbum'Knotweed
- Polygonum albinumKnotweed
- Polygonum amplexicaulered bistort, mountain fleece
- Polygonum amplexicaule 'Arun Gem'Red Bistort
- Polygonum amplexicaule 'Atrosanguineum'Red Bistort
- Polygonum amplexicaule 'Inverleith'Knotweed
- Polygonum amplexicaule oxyphyllum of gardensKnotweed
