The thread knotweed (Polygonum filiforme or Persicaria filiformis) is a leaf ornamental perennial with broadly lanceolate leaves, which have a very striking pattern in some varieties. In September and October, red, slender and thread-like flower spikes appear. The plant grows up to 80 centimeters high and is also very suitable for pot culture.
The variegated knotweed is one of several knotweed perennials
location and use
The knotweed fits very well in shady beds and gives dark corners of the garden an interesting touch. The plant thrives very well in moist, humus-rich soil in partial shade to shade. A spot with morning or evening sun is ideal; the knotweed lets its leaves droop in the midday sun. The soil should also be slightly acidic to neutral and as low in lime as possible. You should plant between six and nine plants per square meter. In contrast to other knotweed, the thread knotweed does not tend to proliferate.
Popular Varieties
'Lance Corporal' has red-brown V-shaped markings on the leaves, 'Painter's Palette' has very interesting red, white and yellow spotted leaves.
maintenance and propagation
The knotweed, native to North and Central America, is very easy to care for and is also considered frost hardy, but a light winter protection is necessary. Propagation is by herbaceous cuttings in early summer. The species also self-seeds. In addition, large specimens can also be propagated by division. Both when planting and every year at the beginning of the growing season in spring, you should thoroughly work organic fertilizer, such as horn shavings (32.93€) or compost, into the soil. The perennial has a very high water requirement, which is why you should definitely avoid drying out the soil. Regular watering is therefore essential in midsummer or during longer dry periods.
tips
Other interesting knotweed perennials are, in addition to the thread knotweed, the candle knotweed (Persicaria amplexicaulis), the sorrel knotweed (Persicaria lapathifolia) and the variegated knotweed (Persicaria microcephala). The edible meadow knotweed (Bistorta officinalis) can also be cultivated as a perennial in the garden.