Little known to us until a few decades ago, Japan’s knotweed is now in the limelight, ranking in the top 100 most problematic invasive plants. Let us talk about this plant in detail. Visit this site for japanese knotweed uk.

Botanical description

-Fallopiajaponica, formerly also called Polygonumcuspidatum is a particularly vigorous perennial herb.

-The stems, very branched at the top, are hollow. In winter, the plant dries up and disappears completely … But in spring, the green-glaucous stems can grow from two meters per month and reach 4 to 6 meters at the end of the vegetative season. Click here for japanese knotweed uk.

-The oval-triangular leaves of Japanese knotweed are petiolate and alternate. They can reach 15cm long in F. japonica and 30cm in R. sachalinensis.

Small white flowers grow in clusters at the axils of the crown leaves in late summer or early fall.

-Persistent rhizomes, long (up to 7 to 10 meters around the massif) and deep (an average of 4 meters deep for the massifs in place), are capable of storing exceptional reserves (which can allow the plant to regrow after 10 years of latency). These rhizomes secrete into the soil exudates whose toxins inhibit the growth of other plants.

Vegetative multiplication

In Europe, the reproduction of this plant is mainly by vegetative propagation.

-By the rhizomes (a fragment of less than 5g is enough to constitute a propagule);

-By cuttings of stems.

Impacts on biodiversity

-Having no predator or competitor in Europe capable of regulating its spread, Japanese knotweed grows in colonies whose density leads to monospecific stands.

-Its strengths for competition with other species are:

-Rapid development from the beginning of spring thanks to the exceptional reserves of its rhizomes;

-Density of foliage obscuring sunlight for other species;

-Emission of toxins into the soil;

-Highly efficient vegetative propagation system .

Impacts on the river

In winter, when the aerial part of the plant dries, it is carried away by the floods, causing jams and favoring the erosion of the banks thus laid bare.