What does it look like?
Holly-leaved senecio is an erect perennial herb that grows up to 1.5m high. It has oval leaves, which are coarsely toothed, and holly-like. The flowers are purple, mauve or pink and occur in clusters. It can be mistaken for purple groundsel (Senecio elegans), an introduced plant that grows in sand dunes and also has a purple-crimson flower.
It mainly grows near the coast and is primarily a plant of partially stabilised sand dunes and disturbed sites. It can also grow on rocky banks, coarse river gravel, coastal scree, sandy substrates and soils. In addition to sand dunes, it has also been recorded in waste places, hillsides, rough grassland, scrubland, and road cuttings.
Why is it a problem?
Holly-leaved senecio is an aggressive invader that is a threat to dune and coastal sites. It has some tolerance of salinity, as well as high soil moisture for limited periods, but is unlikely to tolerate permanently saturated soils. It can grow successfully in sand dune swales and swamp margins.
Holly-leaved senecio reproduces by seed from flowers, which are produced over a short period in October. A few plants have a second, smaller burst of flowering in January/February and set seed in March.