Weeds - Identification of Injurious Weeds (PB4192)

Senecio jacobaea

Mature plant

Young plant (Maggy Milner)

Senecio jacobaea Common Ragwort

A, plant; B, a lower leaf; C, flowering branch D; disc flower; E, corolla of disc flower, partly cut away to show the stamens, and the style; F, mature achene from disc flower some of the pappus cut off. Not to scale.

Young plant:

Young plants of common ragwort are evident from the autumn to early June as low rosettes in pasture and on bare ground. The leaves of these young plants are extremely variable, either undivided or simply divided into terminal oval and smaller lateral lobes. These are usually a deep bottle-green, tinged purple, and slightly glossy on the upper surface.

Adult plant:

In their second or subsequent years the rosettes mature and produce flowering stems from late June onwards. These are between 30-100cm tall, carrying dense flat topped clusters of bright yellow daisy-like flower heads each 1.5-2.5cm across. The leaves on mature plants are strongly divided into narrow lobes with the bases clasping the non-woody main stem. The flowering stems die back after producing seeds.


Other ragwort species not prescribed in the Weeds Act 1959:

Marsh ragwort Senecio aquaticus:

Mature plants have elliptical or oval basal leaves. Upper leaves are less divided than those of common ragwort with larger terminal lobes. The flower heads are also generally larger at 2.5-3cm diameter.

Oxford ragwort Senecio squalidus:

Mature plants, which may have woody lower stems, rarely exceed 50cm in height, and have more widely spaced lobes on the leaves than common ragwort.

Hoary ragwort Senecio erucifolius:

Much more hairy that common ragwort, particularly on the leaf under-surface which is greyish in appearance.

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