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Knotweed
knotweed
knotweed
In Victorian times, Japanese Knotweed was introduced into Britain as an ornamental garden plant. It has since escaped and spread and has now become a very persistent weed that is difficult to eradicate. Another example is when rabbits were introduced into Australian, and have since grown to such huge numbers, that they are now considered a pest. There are many examples world-wide of introduced species that have decimated the native species, even to the point of extinction.
The successful transfer of the luciferase gene from an animal to a plant indicates that the basic mechanisms for gene expression are shared by plants and animals.
Japanese knotweed is a herbaceous perennial plant. It can be found in Japan or you can buy it on the internet or at various gardening stores.
The plant, Japanese Knotweed, is a good example of an invasive species the UK, but ragwort isn't because it is a native plant there.
Japanese knotweed is such a good competitor because it forms thick, dense colonies that crowd out any other herbaceous species and is now considered one of the worst invasive exotics in parts of the eastern United States. The success of the species has been partially attributed to its tolerance of a wide range of soil types, pH and salinity. Its rhizomes can survive temperatures of −35 °C (−31 °F) and can extend 7 meters (23 feet) horizontally and 3 meters (9.8 feet) deep, making removal by excavation extremely difficult. The plant is also resilient to cutting since it vigorously re-sprouts from the roots.
Knotweed
knotweed
knotweed
More than a century is the length of time that Japanese knotweed has been in the United States of America. The invasive plant in question (Polygonum cuspidatum) may have been introduced sometime in the late 1890s to control erosion and screen landscapes. Unfortunately, its tolerance of drought, heat, salinity and shade was counterbalanced by takeovers of low-lying areas, riverbanks, stream-sides, utility rights-of-way and waste places.
The span between growing and flowering is the amount of time that it takes Japanese knotweed to sprout upwards after being chopped down. The herbaceous plant in question (Fallopia japonica) numbers among plants like butterfly bush (Buddleia spp) that tolerate extreme, severe pruning to ground level. But the stress ultimately will be fatal if the cutback occurs multiple times within a year.
The scientific or taxonomic name would be Polygonum douglasii.
The best way to eradicate the invasive Japanese knot weed plant is by digging it up completely including all roots. This is a difficult task and it best suited for undeveloped land. The next most effective way would be by using herbicide in the late summer or very beginning of fall.
That it is non-native and that its cultivation is uncontrolled are reasons why Japanese knotweed is a problem in the United Kingdom but not in Japan.Specifically, the plant in question (Fallopia japnica) can be found growing natively in Japan. It functions as a food source through its honey production and rhubarb-tasting young stems. It also is an alternative to grapes in promoting well-being. It therefore will be found growing as a cultivated plant whose overgrowth is contained by regular trimming and limited by the presence of its natural enemy, predatory psyllid insects (Aphalara itadori).A native plant with aggressive, invasive tendencies often can be controlled in its homeland because of predator-prey interactions. The constraints of a natural enemy -- or of use whose realization involves growth-limiting stress, which happens when a plant repeatedly faces controlled burning, spraying and trimming -- may be lacking outside native ranges.
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