Notice the plant's arching habit: this helps in blocking the light to extant flora and out-compete them.
Also, in tandem with its brittle stems, this increses the chance of reproduction by mechanical means(and it is by such that the plant reproduces itself): fragments of live plant material will stand a good chance of generation if a nodal segment breaks off and germinates in water or soil. Car tyres, footwear, animal and pedestrian disturbance, strimming or cutting are all vectors for its spread.