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Warning! Japanese knotweed threatens the Spree near Bautzen!
Bautzen, July 2, 2025: Experts warn about the spread of Japanese knotweed in the Spree and its consequences.
Warning! Japanese knotweed threatens the Spree near Bautzen!
A paddling trip on the Spree near Bautzen led Bodo Thiemann, CDU city councilor and entrepreneur, to an alarming discovery: plant material was clearly visible floating in the water, which was strongly reminiscent of freshly cut bamboo. It soon turned out that it was Japanese knotweed, a plant that is considered invasive and can significantly disrupt the ecological balance. In a report by Sächsische.de it is mentioned that the State Dam Administration (LTV) of the Free State of Saxony has confirmed the presence of this neophyte in the Spree.
Originally from East Asia, Japanese knotweed was introduced to Europe as an ornamental plant in the 19th century. The tough perennial grows quickly and is particularly difficult to control because it sprouts from even the smallest parts of the rhizome. Tree trunks that lie in the water also accumulate flotsam and create ideal conditions for the plant to spread. “The embankments are endangered by this plant, and native river vegetation is displaced,” says Bodo Thiemann.
The challenges in combating it
A ?complete fight? According to the experts, it is hardly possible to eliminate Japanese knotweed in Saxony. The LTV has measures to combat it, but these are only carried out selectively and after individual examination. “We regularly check sections of water, but we do not have a comprehensive removal strategy,” explains an LTV representative. Thiemann has drawn the attention of the Lower Water Authority to the contamination that could arise from improper disposal of garden waste.
Dr. Heiko Korsch, a botanist, points out in an article by MDR.de points out that there is no ban on this plant in Germany, but its cultivation is clearly not recommended. In Switzerland and Great Britain, the planting and toleration of this species is even prohibited. To remove knotweed from gardens, patience and persistent handling of the plant are necessary, Korsch recommends. If the roots are not completely removed, the plant will grow back quickly.
About the plant itself
The perennial Fallopia japonica, as Japanese knotweed is botanically called, can reach a height of up to four meters. Its strong rhizome can penetrate up to two meters deep into the ground and serves as an overwintering organ. “The above-ground parts die off with the first frost, but it is guaranteed to win medals for the fastest growth,” explains mein-schoener-garten.de, because the plants grow up to 30 centimeters per day during the main growing season.
Given the potential dangers posed by Japanese knotweed, there is an urgent need for action. It is everyone's responsibility to dispose of garden waste safely and not to pollute nature with invasive species. If everyone made a little effort, the spread of knotweed could perhaps be contained.