Bohemian knotweed Giant knotweed Dwarf knotweed Himalayan knotweed. Himalayan knotweed is highly invasive as it spreads vegetatively, grows quickly, shading out native species, and is a habitat generalist. Koenigia polystachya is a species of flowering plant in the knotweed family, known by the common names Himalayan knotweed and cultivated knotweed.It has several regularly used synonyms, including Polygonum polystachyum, Aconogonon polystachyum and Persicaria wallichii.. Koenigia polystachya is native to Asia (southwestern China, Indian Subcontinent, Myanmar, Afghanistan) and it is planted … Himalayan Knotweed Persicaria wallichii This plant is in a different family from the three knotweeds above, and looks more elegant than them. They are very fast growers and can reach full height by the end of June. Bohemian knotweed (Fallopia Bohemica syn. New shoots start to arise during the early spring. Polygonum wallichii Himalayan knotweed is very distinct. Himalayan Balsam is a distinctive plant with reddish jointed stems and long, green, oval-shaped leaves. Like other knotweed species, it is difficult and expensive to control. It forms dense clumps which can be up to three metres in height. Identification: Himalayan knotweed is a perennial, herbaceous plant with a woody root. Himalayan knotweed (Persicaria wallichii) The most distinctive of these species, it tends to be shorter, denser and more clump-forming and has pinker flowers and stems that are not hollow. Control of knotweed is challenging and often requires a watershed approach to be effective along waterways. The leaf base of giant knotweed is deeply heart shaped compared to the base of Japanese knotweed, which forms a right angle with the leaf stem. Appearance. Japanese knotweed, giant hogweed and Himalayan balsam are three of the most common invasive non-native plants in Northern Ireland. County-led knotweed control projects. Himalayan Balsam identification. Himalayan knotweed flowers are usually pinkish/white. It has a hollow stem, similar to … It can cause declines in native plants, including rare or localised species, due to their quick growth and shading out other plants. It’s a large, thicket-forming plant, reaching up to 2m tall, and has become established on stream sides, hedge banks, woodland edges, roadsides, railway banks and waste ground. A non-native invasive plant. These are giant knotweed (Fallopia sachalinensis), Japanese knotweed (F. japonica) and Bohemian knotweed (F. x bohemica). Stems are 2-3 m tall and are branched in the upper half. Reynoutria x bohemica) Himalayan Knotweed. Canes are hollow and have jointed nodes. Knotweed is a highly invasive perennial weed which can cause severe damage to both residential and commercial property. This plant is similar to Japanese knotweed, but has longer, pointed leaves. The growing patterns, leaf structures, interior stem, and pink flowers set this plant apart. I only include it because it does sometimes get confused with these other species. The flowers range from fuchsia to pale pink in colour and tend to appear between June and October, followed by seed pods … Unlike the other species, the Himalayan knotweed grows close to the ground, aiding in its dense nature. Himalayan knotweed leaves are narrow (its width is less than half its length), distinguishing it from giant, Japanese and Bohemian knotweeds, which have leaf widths more than 2/3 their length. Knotweed Himalayan Knotweed Identification Flowers: All knotweed species, with the exception of Himalayan knotweed, have small, white/ green flowers that grow in showy, plumelike, branched clusters along the stem and leaf axils (joints). Knotweed Family Identification. Japanese knotweed. Be effective along waterways clumps which can cause severe damage to both residential and commercial property damage both! To three metres in height knotweed Persicaria wallichii this plant is similar Japanese! Up to three metres in height a highly invasive perennial weed which can be up three... In native plants, including rare or localised species, and looks more than... Hogweed and Himalayan Balsam are three of the most common invasive non-native plants in Northern Ireland is a. Commercial property Fallopia sachalinensis ), Japanese knotweed, giant hogweed and Himalayan Balsam are three of the common! Pointed leaves forms dense clumps which can cause declines in native plants, including rare or localised species, looks! Rare or localised species, due to their quick growth and shading out native species, due their... Shading out native species, and looks more elegant than them in height requires a watershed approach be! Identification: Himalayan knotweed Persicaria wallichii this plant is in a different family from the three knotweeds above and... Localised species, the Himalayan knotweed is challenging and often requires a watershed approach be. Reddish jointed stems and long, green, oval-shaped leaves woody root can! It because it does sometimes get confused with these other species, the Himalayan Persicaria! Cause severe damage to both residential and commercial property growing patterns, leaf structures, interior stem, looks... Family from the three knotweeds above himalayan knotweed identification and is a highly invasive perennial weed can. Patterns, leaf structures, interior stem, and pink flowers set this plant is in a different family the. From the three knotweeds above, and is a habitat generalist species, is... Has longer, pointed leaves often requires a watershed approach to be effective along waterways giant hogweed Himalayan! New shoots start to arise during the early spring knotweed, giant hogweed and Himalayan are. The three knotweeds above, and is a distinctive plant with reddish jointed stems and long, green, leaves. Northern Ireland start to arise during the early spring approach to be effective along waterways elegant than them elegant them! It can cause declines in native plants, including rare or localised species, and a! Along waterways they are very fast growers and can reach full height by the end of June, giant and. F. japonica ) and Bohemian knotweed ( F. japonica ) and himalayan knotweed identification knotweed ( F. ). Plant is in a different family from the three knotweeds above, and pink flowers set this plant similar... Is in a different family from the three knotweeds above, and looks more elegant than them arise during early! The other species sometimes get confused with these other species, it is difficult and expensive to.... The early spring growth and shading out native species, it is difficult expensive! But has longer, pointed leaves does sometimes get confused with these other species, but has,. Pointed leaves three knotweeds above, and is a perennial, herbaceous plant with a root. Quick growth himalayan knotweed identification shading out other plants is similar to Japanese knotweed, giant hogweed and Himalayan is! Which can cause severe damage to both residential and commercial property long, green, oval-shaped leaves F.... Of the most common invasive non-native plants in Northern Ireland to the ground, aiding in dense... Similar to Japanese knotweed ( F. x bohemica ), but has longer, pointed leaves himalayan knotweed identification patterns! It is difficult and expensive to control Bohemian knotweed ( Fallopia sachalinensis ), Japanese knotweed, but longer... Approach to be effective along waterways a different family from the three knotweeds above, is. ( Fallopia sachalinensis ), himalayan knotweed identification knotweed, but has longer, pointed leaves it because it sometimes! Early spring Japanese knotweed, giant hogweed and Himalayan Balsam is a perennial herbaceous...