Ragwort

Senecio jacobaea
Other names: Ragweed, Tansy Ragwort, Staggerweed, Stinking Willie
Family: Compositae

Common Ragwort is usually considered to be a biennial, over-wintering either as seeds or as rosettes. It is also capable of becoming a short-lived perennial if the flower stem is cut (eg. in the lawn), but usually it dies after producing seeds. The leaves are light to dark green and deeply lobed. The lower leaves form a rosette which is present from autumn to late June and dies back when the main stem develops before flowering starts in late summer of the second year.

It grows 30-100 cm high with woody stems which are red at the base. The upper part of the stem is branched and bears yellow flower-heads in large dense flat-topped terminal clusters, nearly always rayed, and daisy-like. A single plant can produce over 150,000 white downy seeds, which are carried away by the wind, and which can remain viable in the soil for up to 15 years.

The foliage is attacked by the caterpillar of the Cinnabar Moth and they have been used as a biological control.

All parts of the plant contain alkaloids that are toxic to cattle, deer, pigs, horses and goats, causing liver damage, and death is slow often occuring months after ingestion. Sheep are less affected, but should not consume the weed as the liver damage can be cumulative. The foliage has a distinctive unpleasent odour when crushed so poisoning by grazing is rare as it is instinctively avoided. If the plants are carelessly cut and left around to wilt, they become palatable and the alkaloids are still potent, so grazing animals can be poisoned.

It is possible therefore for dead plants to be incorporated into silage or hay and this is the main cause of Ragwort poisoning. Great care must be taken to avoid this happening. The flowering stems should be developed when the forrage is being saved, so any plants are easily spotted before cutting commences.

Silver Ragwort (Senecio cineraria syn. Cineraria maritima), a subshrub, is a close relative. It is usually called Cineraria and is used for its 'silver' foliage in annual bedding plantings. If allowed to develop, in subsequent years it will produce upright stems with flowers very similar to those of Common Ragwort. When growing in close proximity the Common and Silver Ragwort can hybridise

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