The red bistort is a valuable, cluster growing summer bloomer with elegant flower candles that keeps its flowers until the first frost. Here are tips on planting and more details of the easy-care perennial.
Profile of red bistort:
Scientific name: Bistorta amplexicaulis
Plant family: knotweed family (Polygonaceae)
Other names: mountain fleece
Planting time: spring, after frosts
Flowering period: June to October
Location: sunny to partially shaded
Soil quality: sandy to loamy, moderately nutrient-rich to nutrient-rich, humus rich
These information are for temperate climate!
Use in: flowerbeds, bouquets, ground cover, stand-alone, group planting, pond planting, underplanting, borders, cottage garden, flower garden, natural garden, park area, prairie garden, forest garden
Winter hardiness: hardy, USDA Plant Hardiness Zones: 5 (-26 °C / -15 °F)
Bee and insect friendly: Yes
Plant characteristics and classification of red bistort
Plant order, origin and occurrence of red bistort
The red bistort (Bistorta amplexicaulis) originally grows in shady meadow locations and in the forests of the Himalaya. But it has also been enjoying growing popularity with us for several years, because the perennial is easy to care for, is spared from snails and flowers well into autumn. When it comes to knotweed, many initially think of the proliferous Asian or Japanese knotweed (Fallopia japonica), a neophyte that very few people would like to have in their own garden.
The red bistort has little in common with this species of knotweed, apart from the fact that they both belong to the knotweed family (Polygonaceae). In contrast to the Asian knotweed, the red bistort grows cluster, does not spread by runners or self-sowing, flowers beautifully and is therefore a valuable garden perennial. Only its botanical name often leads to confusion and has changed several times in the past. So Bistorta amplexicaulis also bears the synonyms Persicaria amplexicaulis and Polygonum amplexicaule. This is due to changes in the nomenclature.
Characteristics of red bistort
The red bistort are clustering growing perennials that can be up to 120 centimeters (48 in) high. The branched stems rise from a dense cluster of leaves, with the conspicuous candle-shaped flowers at the ends.
The broad, lanceolate leaves of the red bistort have a slightly wavy edge and are between 5 and 15 centimeters (2 and 6 in) long. They grow to encompass the stems. Therefore, at first glance, it looks like they are heart-shaped. The leaves form a dense cluster of leaves covering the ground and often turn yellow in autumn.
The slender flower candles bloom from August to October and sometimes until the first frost. The red flowers are valuable color carriers in the garden. But there are also varieties of white and rose-red. Red bistort also has the nice property of always sprouting new buds after the main bloom.
The red bistort forms only very inconspicuous fruits.
Red bistort – cultivation and care
The optimal location for the red bistort is in full sun. But it also gets along well in a slightly shaded location.
Red bistort likes to grow in loamy, nutrient-rich, fresh to moderately moist garden soil. But it also grows on drier soils. However, it doesn’t like waterlogging at all.
Planting red bistort
Because red bistort is at risk of late frost, it is best to plant it in the spring after the last frosts. When planting several specimens, be careful not to put the perennials too closely together, since mountain fleece does not like this tightness in the early years. You should therefore plan enough space in a bed so that the plants can grow well. One plant per square meter is optimal
Care / Fertilization / Pruning
The red bistort is quite undemanding and robust. If necessary, the perennial can be supplied with compost in spring. If the plant falls apart after a heavy downpour, it is advisable to trim the outer stems back to the wide leaf knot above the ground. After just two to three weeks, the newly formed shoots are in full bloom again. If you prune the red bistort back to leaf level immediately after flowering and then supply the plant with a fast-acting fertilizer, some varieties will bloom a second time. You should leave the dead leaves lying around as a protective mulch cover in winter, as the rhizomes of the perennial, some of which protrude from the ground, are somewhat sensitive to cold frosts. Giving some compost in autumn can also help here.
Red bistort is, like all other knotweed, very long-lived and therefore does not have to be rejuvenated regularly by division. Dividing in late spring is a good way to propagate the plants.
Since for the most part only cultivations of the red bistort are used in our gardens, real propagation is only possible by dividing or cuttings. While the division is carried out in late spring, the cuttings are propagated in early summer.
Diseases and pests
With the red bistort there are usually no problems with diseases and pests, the perennials are not even eaten by snails. If the location is too dry, spider mite infestation can occasionally occur, but this does not particularly damage the plants and usually takes care of itself as soon as the weather becomes cooler and more humid.
Red bistort is hardy down to -26 °C / -15 °F. As a winter protection a layer of mulch or brushwood is useful. You should also leave the dead leaves lying around as the rhizomes of the perennial are somewhat sensitive to cold frosts.
Use in the garden
The pretty red bistorts are very valuable perennials for the garden, as they are not only easy to care for, but also grow quickly and present their flowers for a very long time. They also thrive in different locations, which is why they are very versatile. Red bistort, for example, are suitable for planting the edges of a sunny garden pond as well as for partially shaded garden areas, where their flower candles create nice splashes of color. Because of their long flowering period, red bistort is also very popular with bees. Beautiful plant combinations result with other late-blooming perennials such as Japanese anemones (Anemone hupehensis) or bugbanes (Cimicifuga) and ornamental grasses that play around the elegant flower candles. But asters and phlox, whose flowers move in the same color spectrum, are also attractive partners.
Numerous varieties of red bistort are now available in stores. Most often you can see red bistort in strong red tones such as the ‘Fat Domino’, but varieties in white and pink are also enjoying increasing popularity.
- ‘Album’: One of the few white-flowering varieties that, despite its subtle flower colors and a growth height of up to 120 centimeters (48 in), is one of the more conspicuous representatives of this species
- ‘Blackfield’: A newer variety that bears dark red flowers, with intense luminosity, from July until the first frost. In addition, the leaf margins turn slightly red in autumn. The variety reaches heights of 80 to 100 (32 to 40 in) centimeters
- ‘Firetail’: A classic among the red bistort and also under the name ‘Speciosum’ in stores. This variety delights with bright scarlet red flower candles, is 120 centimeters (48 in) high and is considered particularly hardy
- ‘Inverleith’: Because of its pillow shape, the only 50 to 60 centimeter (20 to 24 in) high variety is often used as a ground cover for the foreground, in narrow bedding areas, small gardens and mixed plantings
- ‘Roseum’: With its delicate pink, narrow flower candles, this variety is ideal for beds in pastel shades. It is not quite as showy as other varieties, but is perfect for anyone looking for a plant that brings calm to the bed. It is 120 centimeters (48 in) high