Overview
Polygonum polygaloides Wallich ex Meisn. ssp. polygaloides also known as the purple stemmed smartweed or Purple Knotweed is a member of the family Polygonaceae. This plant is native to North America and is found in different regions across the continent. It grows mostly in damp habitats such as along riverbanks, marshes and wet meadows.
Appearance
The Purple Knotweed is a creeping perennial herb with reddish-purple stems that can grow up to 3 feet tall. The leaves are alternate and lance-shaped, with smooth edges and a pointed tip. The flowers are small and pinkish-white, clustered tightly in slender spikes that measure up to 6 inches long. The fruits are small and triangular with shiny black surfaces.
Common names
This plant has several common names including Purple Knotweed, purple stemmed smartweed, swamp knotweed, and water knotweed. In some regions, it is referred to as the marsh pepper or smartweed.
Uses
Historically, Native Americans used the Purple Knotweed for medicinal purposes such as treating headaches, diarrhea, and respiratory problems. The plant is astringent, expectorant, and diuretic, making it helpful for treating urinary tract infections. Today, the plant is rarely used for medicinal purposes but is instead grown in gardens as an ornamental plant.
Light Requirements
Polygonum polygaloides Wallich ex Meisn. ssp. polygaloides thrives in a variety of lighting conditions. However, the plant requires full sun to partial shade. Partial shade is ideal as the plant can be damaged by the intense heat of the sun in some regions.
Temperature Requirements
The plant is native to a wide range of areas and can tolerate various temperatures. However, the optimal temperature range for growth is between 15-30 degrees Celsius. In extremely cold regions, the plant may not thrive, but it can withstand temperatures as low as -10 degrees Celsius.
Soil Requirements
Polygonum polygaloides Wallich ex Meisn. ssp. polygaloides requires well-draining, fertile soil to grow. It is not particularly demanding when it comes to soil type and can grow successfully in sandy, loamy or clayey soils. The soil pH should be between 5.0 and 8.0. The plant does not perform well in water-logged or heavy clay soils.
Cultivation Methods
Polygonum polygaloides Wallich ex Meisn. ssp. polygaloides is a relatively easy plant to cultivate. It can grow in different types of soils, from sandy to loamy, and even in soils with poor drainage. This plant prefers full sun to partial shade, but it can also grow in shady areas. It can tolerate cold temperatures but not frost. In warmer climates, it is recommended to grow this plant in a shaded area to protect it from sunburn.
Watering Needs
This plant prefers moist soil, but it can also tolerate a dry period. Watering should be done regularly during the growing season, but the soil should not be left waterlogged as it can cause root rot. It is recommended to water this plant when the top layer of soil is dry. In areas with high rainfall, watering may not be necessary.
Fertilization
Polygonum polygaloides Wallich ex Meisn. ssp. polygaloides does not require heavy fertilization. A balanced fertilizer, with equal parts of nitrogen, phosphorus, and potassium, can be applied during the growing season. Fertilization should be done sparingly, as excessive use of fertilizer can cause the plant to produce more foliage than flowers.
Pruning
This plant does not require extensive pruning, but it benefits from occasional trimming to promote bushier growth. Deadheading spent flowers can also promote more blooms and prevent self-seeding. Pruning should be done after the flowering season to avoid removing new growth. Cuttings can be taken during the growing season and rooted in a well-draining soil mixture.
Propagation of Polygonum polygaloides Wallich ex Meisn. ssp. polygaloides
Polygonum polygaloides Wallich ex Meisn. ssp. polygaloides, commonly known as candyflower smartweed, is a perennial herbaceous plant that grows in moist to wet habitats. Propagation of this plant can be achieved through seeds, cuttings, division, or layering.
Seed Propagation
Seeds of Polygonum polygaloides Wallich ex Meisn. ssp. polygaloides can be collected from mature plants after they have formed and dried on the plant. The seeds can be sown in a well-draining soil mix in late winter to early spring, and kept moist until they germinate. It is important to keep the soil moist but not waterlogged as this can lead to damping off and the death of young seedlings.
Cutting Propagation
Cuttings of Polygonum polygaloides Wallich ex Meisn. ssp. polygaloides can be taken in late spring or early summer from healthy parent plants. The cuttings should be about 6 inches long and should include at least one node. The bottom leaf should be removed, and the stem dipped in rooting hormone before planting in a well-draining soil mix. The cuttings should be kept moist and in indirect light until they have developed roots.
Division Propagation
Division is another method of propagating Polygonum polygaloides Wallich ex Meisn. ssp. polygaloides. It is best done in early spring before the plant starts to grow. Using a sharp and clean knife, the parent plant can be carefully divided into several smaller clumps, ensuring that each clump has a sufficient root system. The new clumps can then be replanted in a well-draining soil mix.
Layering Propagation
Layering is a technique that involves bending a stem of the parent plant to the ground and pinning it down with a wire or a stake. The stem should be covered with soil and kept moist until new roots have developed. Once new roots have developed, the stem can be severed from the parent plant and replanted in a well-draining soil mix.
Disease Management
While Polygonum polygaloides Wallich ex Meisn. ssp. polygaloides is not particularly prone to diseases, there are still a few potential issues to watch out for. One common problem is powdery mildew, a fungal disease that presents as a white, powdery coating on the leaves and stems. To prevent powdery mildew, make sure to keep the plant well-ventilated and avoid overhead watering that can promote fungal growth. If powdery mildew does appear, you can treat it with a fungicide spray or a solution of neem oil and water.
Another potential disease issue for this plant is root rot, which is caused by overly wet soil and poor drainage. To prevent root rot, make sure the soil is well-draining and only water the plant when the top inch of soil feels dry to the touch. If you do notice signs of root rot, such as wilting leaves or a foul smell, you may need to repot the plant with fresh, well-draining soil to prevent further damage.
Pest Management
Unfortunately, Polygonum polygaloides Wallich ex Meisn. ssp. polygaloides is vulnerable to a few common pests that can cause damage to the leaves and stems. One of the most common pests is the spider mite, which feeds on the plant's sap and can cause leaves to yellow and drop off. To control spider mites, you can try spraying the plant with a solution of water and neem oil or using an insecticidal soap spray.
Another potential pest issue is the whitefly, a small insect that feeds on the plant's sap and can cause leaves to turn yellow and wilt. To control whiteflies, you can try using yellow sticky traps to catch the insects or spraying the plant with a solution of water and insecticidal soap.
Finally, aphids are another common pest that can affect Polygonum polygaloides Wallich ex Meisn. ssp. polygaloides. These small insects feed on the plant's sap and can cause leaves to curl and distort. To control aphids, you can try spraying the plant with a solution of water and insecticidal soap or introducing natural predators like ladybugs or lacewings into the environment.
