Common Ragwort (Senecio jacobaea)
This is the food plant of the Cinnabar Moth larvae (Tyria jacobaeae) and at least 76 other insect species. It also provides a further 117 species with a source of nectar. These species include solitary bees, hoverflies, moths and butterflies such as the small copper (Lycaena phlaeas). There are 30 species that feed exclusively on ragwort seven of which are deemed nationally scarce and three are on the red list of endangered insects. The U.K. Biodiversity Action Plan lists the Sussex Emerald Moth (Thalera fimbrialis) as a Priority Species.
Thus the Common Ragwort’s vital role in maintaining biodiversity cannot be denied and needs to be appreciated.
Against this ragwort contains many types of alkaloids making it poisonous to animals such as horses and cattle. Luckily these animals avoid fresh ragwort due to its bitter taste. However if this plant is found in fields cut for hay it presents a real danger. When dried it loses this bitter taste and is therefore palatable to horses and cattle alike. If consumed in sufficient quantities it causes cirrhosis of the liver and the animal will succumb.
In the United Kingdom Common Ragwort is one of five plants named as an injurious weed under the provisions of the Weeds Act 1959. In practice this means that a landowner can be required by D.E.F.R.A. to control the spread of this plant but there is no statutory obligation for control in general.
This plant thrives more or less anywhere but specifically in rough pasture, rabbit-grazed areas, scrub, waste ground and roadsides. Its presence on Bepton Down is tolerated but it should not be allowed to takeover which it could readily do as it would have a detrimental effect on species specific to chalk downland.
It is easily recognisable through its tall, erect, branched habit. It may stand up to 1m tall. The leaves are produced laterally and are irregularly lobed. The hermaphrodite flowering heads are 1.5 – 2.5 cm in diameter, and are borne in dense, flat-topped clusters. The florets are bright yellow and the plant will flower freely from June to November. It is considered to be a biennial plant but does have perennial tendencies when certain conditions are met.