Japanese knotweed

The Japanese knotweed is the common name given to the plant species known by the scientific name of Polygonum cuspidatum (aka Fallopia japonica). The Japanese knotweed is an invasive plant that is native to Eastern Asia. It can know be found in the mainland of Europe, most of the British Isles, at least 36 states of the United States Of America, throughout Canada, New Zealand and also Newfoundland.

The Japanese knotweed is known for destroying the value of homes and destroying its surroundings if not taken control of. The Japanese knotweed usually grows in areas with partial shade and rich, moist soil. It can tolerate in drier exposed sites but its growth is decreased in this type of area. The control methods to get rid of this invasive plant can begin at $5000 and can quickly rise to $25,000 and can go even higher. If one small bit of root is left behind in the ground it can grow right back without the proper care.

Body Design
The Fallopia japonica can grow up to 6.5 feet tall and 65 feet wide due to its incredibly fast rate of growth. Another feature of the Japanese knotweed that makes it so unstoppable and invasive is its relentless army of underground roots. The plant can grow up to 2m in one season. The Japanese knotweed has stalks that are spotted with purple. The stalk itself is hollow and grows up to be extremely tall if not controlled. The leaves of the plant are heart shaped, and the roots of the Japanese knotweed become unbelievably tangled and are strong enough to penetrate through the ground or even the walls of homes if the ground underneath it is not inspected beforehand.

The pattern of the leaves on this plant go in a zig-zag pattern. The leaves, when felt, feel rough and thick in texture. The flowers of the Japanese knotweed are relatively small compared to the rest of the rest of its body. They can be creamy white to greenish white in color and they grow out of the plant in a showy, plume-like fashion.

Life Cycle


Like all plants, the Japanese Knotweed, or Polygonum cuspidatum, starts as a seed. These seeds are usually spread through movement of plant parts. When there is an adjacent pollen source, large amounts of seed can be produced. In the spring, the plant begins to grow and the stems elongate very rapidly. After just a few weeks, a large, green canopy has been created that blocks out most light.

The plant, while young, looks like giant asparagus sticking out of the ground. Seeds start to travel and more Japanese Knotweed begins to grow. It grows fast and extremely aggressively. When fully grown, Polygonum cuspidatum can reach up to fifteen feet in height. Plant growth above is very frost sensitive and dies if it becomes frozen. The Japanese Knotweed dies during the winter months. When spring returns, the cycle starts again.

Ecology


Japanese knotweed is an extremely invasive species; native to Asia but spread to Australia, Belgium, Canada, Czech Republic, Denmark, France, Germany, Guernsey, Ireland, Isle of Man, Italy, New Zealand, Russian Federation, Saint Pierre and Miquelon, Slovakia, United States (USA), and United Kingdom (UK). The plant is known for being able to withstand many different conditions. This is also one of the reasons it is so invasive and able to flourish so well. In Japan, it's native country, natural enemies keep it under control.

It seems to prefer coastland, riparian zones, ruderal/disturbed, urban areas, water courses, and wetlands. The knotweed flowers in autumn. Polygonum cuspidatum is able to survive in extreme conditions which include absolute shade, extreme temperatures both high and low, high salinity (saltiness), and drought. It can usually be found around river banks because it prefers low-lying and disturbed areas. In Asia, it grows on volcanic soils with a pH less than 4 and can grow in silt, loam, and sand with a pH between 4.5 to 7.4. Its distribution seems limited by light and is usually found in open sites.

Invasive Behavior


The Japanese is highly invasive and has been introduced to 38 US states and several different countries around the world. The Japanese knotweed causes major problems to native species. It is spread by the cuttings of rhizomes usually accidentally as they're discarded from gardens or carried along rivers or stream beds, where it can regrow extremely quickly after floods. This violent plant grows within 6 days and takes over river/stream banks. After the first couple months of spring, it grows to over 6 feet whose shade will trouble or even kill the other species around it. Even when the knotweed leaves and stems are destroyed, finally eliminating it is extremely difficult as the rhizomes will sustain it. It can withstand almost all types of soil, light, and drought conditions. It has been declared a noxious weed in several states. Because the leaves and stems fall thickly and take a long time to decompose, no other plants can grow in an area choked with the Japanese knotweed.

It is so difficult to get rid of, it’s illegal to plant in the wild in the UK. It can grow through floors of houses, asphalt, concrete, walls and into drains and ultimately, nearly always cause significant damage. The Japanese knotweed is known to override and crowd the native species. In the dormant season, it also creates a fire hazard.

Control Efforts
There are many methods of getting rid of knotweed like the Mechanical method. You cut around the perimeter of the infected area and at the bare minimum, five feet down. You must then dig up the remaining roots with your hands. Leaving just a hair of the root is a window of survival the knotweed will use so be certain when using this method. It works best with smaller infestations.

Chemical control is an effective method for riddance of the pest over large areas. You can spray glyphosate all under and on top of the plant's leaves. To ensure its elimination, completely cover the roots with the spray. Completely getting rid of the plant takes year because the prospects of regeneration are so high. It is vital to burn the plant scraps as it can ruin a compost pile. The shoots can be eaten by certain animals, but this doesn't eliminate the plant, only controls it. Efforts are put into trying to find more efficient and economical ways to finally rid of the Fallopia japonica.

Video
Japanese knotweed identification methods, control methods and information on this invasive species 35hmwZ4MlLM