Originally from Asia, Japanese knotweed (Reynoutriajaponica var.  Japonica, syn.  Fallopia japonica) was introduced in North America as an ornamental in 19th century. This fast-growing perennial reaches 2 to 3 m in height during the summer. Its hollow and gnarled stems are similar to those of bamboo, hence the names of Japanese bamboo or Mexican bamboo sometimes attributed to it. At the end of the season, she produces panicles of creamy white flowers. Click here for japanese knotweed damage.

One of the worst trees

At first glance, these features may appeal to the gardener, but do not be fooled! This beautiful plant is among the 100 worst invasive species on the planet according to the World Conservation Union (IUCN). Cultivars with variegated foliage are also invasive. Visit this site for japanese knotweed damage.

The Japanese knotweed has rhizomes that can sink to more than 2 m deep and hear laterally on 7 m! These underground stems release toxins that prevent the establishment of other plants.

In North America, the plant reproduces mainly vegetatively, but this mode of reproduction is very effective: a tiny piece of stem or rhizome can give birth to a new plant.

In addition, rhizome fragments can remain dormant in the soil for 10 years. Finally, the absence of a natural enemy also facilitates the establishment of this true plague.

Where it is grown

Japanese knotweed colonizes the edges of water bodies, wetlands, ditches, irrigation canals, roadsides and disturbed areas. It is also common in urban areas. We can sometimes see his rhizomes pierce the asphalt!

It forms dense stands that stifle native species, depleting the biological diversity of ecosystems. It also limits access to streams and increases the risk of flooding due to dead stems floating on the surface of the water in the spring.

The eradication of this treejapanese knotweed damage

The eradication of Japanese knotweed is extremely difficult, so it must be avoided at all costs to grow it. If the plant is present in your garden, cut its stems to the ground, and this, several times during the season, so as to exhaust its reserves. You will have to do this for several years.

Do not try to tear it off: its rhizomes are very deep and you may forget fragments in the soil. Do not compost size residues and do not throw them in the wild!

Take care of picking up any cuttings; put them in garbage bags and dispose of them when garbage is collected. Research is under way in England to find biological control methods.