The extremely decorative flowers and the large variety of varieties make the candleweed an increasingly popular perennial, which is also quite undemanding.
The knotweed (Persicaria amplexicaulis) is a real asset in the garden, because it does not require any extensive care and is generally very robust. In addition, it convinces with its long-lasting flowering and rapid growth. In combination with other plants, particularly attractive plantings can be created.
Knotweed: origin and properties
Persicaria amplexicaulis belongs to the knotweed family (Polygonaceae) and is also known by the synonyms Bistorta amplexicaulis anddue to new taxonomic findings. Polygonum amplexicaule known. The natural occurrence of the candle knotweed is in the Himalayan region and extends from Afghanistan to China. There it prefers to grow in fresh to moist perennial corridors and on woody edges in sunny to shady locations.
The deciduous perennial forms bushy clumps with a height of 100 to 120 cm. It gradually spreads out through short spurs. The flower stalks reach up between the densely growing, green foliage, at the tips of which are the candle-shaped flower panicles. They are colored white, pink, pink or red depending on the variety. The flowering splendor of the perennial can be admired for a surprisingly long time - from mid-July to the end of October. The leaves of the candleweed are about 5 to 15 cm long and grow encircling the stem, which is why they form a heart-like shape. The perennial, robust plant is hardy and therefore does not need any special treatment in the cold season.
Is knotweed bee-friendly? Knotweed is a very good nectar and pollen plant and is therefore a food source for insects such as bees or butterflies. Depending on the variety, this property is more or less pronounced.
The most beautiful knotweed varieties for yourGarden
The most striking distinguishing feature of the varieties of the knotweed is usually the color of the flowers.
- Persicaria amplexicaulis ˈAlbaˈ: This bee-friendly variety impresses with its elegant, white flowers from August to October. It grows to a height of 100 to 120 cm and is also suitable as a cut flower.
- Persicaria amplexicaulis ˈAnnaˈ: The ˈAnnaˈ variety reaches an impressive height of 120 to 140 cm and blooms in bright pink from July to October . Insects also enjoy her.
- Persicaria amplexicaulis ˈSaraˈ: This floriferous variety convinces with excellent he alth and stability. It bears showy purple-pink flowers from July to October and grows to a height of 100 to 130 cm. It is also suitable as an insect pasture.
- Persicaria amplexicaulis ˈTaurusˈ: The flowering candleweed ˈTaurusˈ is slightly shorter at 80 to 100 cm in height. Its intense dark red flowers also adorn the perennial from July to October. In addition, this variety often exhibits a decorative red autumn colour.
- Persicaria amplexicaulis ˈOrangofieldˈ: The unusual flower color makes this variety particularly interesting. Because with the salmon pink color it is a real eye-catcher. It reaches a height of 70 to 90 cm and is very willing to flower.
Tip: A related and also popular species is the meadow knotweed (Persicaria bistorta), which is also known as the snake knotweed. It is well suited for sunny and damp locations such as water edges. For example, a popular variety is ˈSuperbaˈ.
Plant Knotweed
The perennial grows optimally in the following location, but it also thrives quite well in other places. Here you can find out more about the most suitable location and give tips on planting.
Tip: The knotweed grows a bit rampant with its rhizomes and can also multiply by self-sowing, but it is not usually a nuisance and is still easy to tame . An advantage of this growth is that weeds are effectively suppressed.
Location and Procedure
Is optimally planting Persicaria amplexicaulis in loosened, fresh to moist loamy soil in a sunny to shady and sheltered position. A nutrient-rich, humus-rich and deep loamy soil is best suited. The knotweed feels particularly at home on woody edges, but also on the banks of water and is ideal for perennial borders and beds of magnificent perennials.
To improve the soil of very sandy, barren soil, plenty of mature compost or high-quality humus-rich soil can be mixed in. Our Plantura organic compost soil, for example, is also suitable for this, as it offers the plant a substrate with good water storage capacity and nutrient availability. Some sand or grit should only be worked into very compacted soil, because the knotweed can even grow well in stagnant moisture.
A good time for planting the perennial is either in spring, mid-May, or in autumn, around September. If several specimens are combined in a group planting, a distance of about 50 cm should be maintained. Under no circumstances should more than three perennials be planted per square meter, as the individual plants will continue to spread over time.
Combining knotweed: good planting partners
A good plant combination with the knotweed results, for example, from the harmonizing flowering time of the autumn anemone (Anemone hupehensis). But asters (Aster), phlox (Phlox) and silver candles (Actaea simplex) are also good as a planting partner. Interesting combinations can be created with ornamental grasses. On the other hand, you should generally avoid smaller plant neighbors with the knotweed, as these would die within a short time due to a lack of light and space.
The right care: pruning, fertilizing and Co.
As already mentioned, no complex measures are necessary when caring for the candle knotweed. In order to give your perennial the best possible conditions for he althy growth, we explain a few tips below.
Watering Knotweed
Freshly planted specimens of the knotweed should not be exposed to longer periods of drought, so the soil around it is better kept well moist. However, well-established perennials can cope with occasional dry periods. Persistent waterlogging can harm the candleweed - especially whenif the soil is too wet in winter, there is a risk that the rhizomes of the plant will rot from fungal attack.
Fertilize
The perennial is not dependent on regular fertilizer application on good soil, but benefits from working mature compost or flower fertilizer granules such as our Plantura organic flower fertilizer into the subsoil in spring. As a result, important nutrients are added to the soil again and soil life is supported.
Cutting Knotweed
By pruning halfway up, the effects of strong winds or rainfall can be offset again and the plant will sprout compactly again within a short time. In some cases, this measure can also cause renewed flowering.
Right abouthibernate
For overwintering, the withered leaves can simply be left on the ground, so the rhizomes are additionally protected from colder temperatures. In particularly wet and cool regions, the perennial can also be covered with brushwood.
Growing Knotweed
Due to the already mentioned self-sowing, the knotweed multiplies reliably in autumn. In the following spring, several seedlings will be visible around the perennial, which can easily be removed or simply transplanted in the event of unwanted propagation.
The best way to propagate yourself is to divide the perennial, which is anyway about should be done every three to four years to rejuvenate the plant. To do this, the candle knotweed is dug up in the spring just before it sprout and the soil is shaken off the roots a little. Now you separate the parts of the plant that have already developed a good root system. All individual parts are now reinserted in the desired position and well cast.
Is knotweed poisonous?
Basically, the knotweed is not a plant intended for consumption. But knotweed and other knotweed species do not contain any toxins and therefore do not pose any danger to humans or animals. However, it should be noted that the plants can contain more or less high levels of oxalic acid, which can cause he alth problems in high concentrations. Children, pregnant women and people with previous illnesses in particular should not eat any of the plant parts. Cats should not eat the plant either, as their bodies cannot break down the oxalic acid. Damage does occur, howeveronly with larger amounts consumed.
Another interesting plant from the Polygonaceae family is the common sorrel (Rumex sanguineus). Not only does it have decorative leaves, it can also be added to salads, for example.