Its dark, deeply-cut leaves are stripped by yellow-and-black banded caterpillars that later become crimson-and-black day-flying moths
Common ragwort - foodplant of the cinnabar moth, Tyria jacobaeae.
Nature · Wildflowers & flowers
Common ragwort
Native · biennial, flowers June to November · grassland, verges, waste ground
Jacobaea vulgaris — Asteraceae
Common ragwort is Britain's most misunderstood wildflower: a native biennial that is poisonous to horses and cattle, yet supports over 200 kinds of invertebrate and is the food of the cinnabar moth's caterpillars. It is an 'injurious weed' under the Weeds Act 1959, but the Ragwort Control Act 2003 did not require anyone to pull it up; it only provided for a code of practice.
How to spot them
- ▸A tall, stiff, branched plant to 1 m with a flat-topped cluster of many bright yellow daisy-like heads, about 13 ray florets each
- ▸Dark green, ragged, deeply cut leaves with a large blunt end lobe; stem often tinged red
- ▸Black-and-orange banded caterpillars of the cinnabar moth crowd the plant in July-August
- ▸A rosette in the first year; flowers in the second
- ▸Look-alike: Oxford ragwort is smaller and branched with looser heads and more finely cut, shiny leaves; hawkweeds and hawk's-beards have undivided leaves
How to know it
An Act of 2003 named after this yellow flower did not make it illegal to grow; it provided for a code of practice on preventing its spread
Common ragwort - the Ragwort Control Act 2003; the Code was published in 2004.
Fresh, it is bitter and animals usually avoid it, but cut into hay it keeps its poison, pyrrolizidine alkaloids, which damage a horse's liver cumulatively
Common ragwort - the danger is in hay and haylage, which is why the Code focuses on fodder fields.
One of the five 'injurious weeds' of the Weeds Act 1959 alongside spear thistle, creeping thistle, curled dock and broad-leaved dock
Common ragwort - Natural England enforces.
More than 200 invertebrate species have been recorded on it, and it is among the UK's flowers most visited by butterflies
Common ragwort - Wildlife Trusts.
Its genus is named for St James, because it flowers around his day; in Scotland it was nicknamed 'stinking Willie', supposedly after the Duke of Cumberland
Common ragwort - Jacobaea from Jacobus (folk etymology for the nickname).
Sheep and goats tolerate this plant far better than horses and cattle, and have been used to graze it down
Common ragwort - species differ in sensitivity to pyrrolizidine alkaloids.
Quick-fire facts
- •Formerly Senecio jacobaea, now placed in Jacobaea; family Asteraceae
- •Native, biennial or short-lived perennial; flowers June to November (Wildlife Trusts)
- •Wildlife Trusts: more than 200 species of invertebrate recorded on it; one of the UK's most frequently visited flowers by butterflies
- •Toxic principle: pyrrolizidine alkaloids, which cause cumulative liver damage in horses and cattle
- •Defra's Code of Practice says it does not seek to eradicate ragwort, a native plant important for wildlife; it targets high-risk situations near grazing or forage fields
- •Weeds Act 1959 lists five injurious weeds: common ragwort, spear thistle, creeping thistle, curled dock and broad-leaved dock
- •The Ragwort Control Act 2003 is a short Act providing for a code of practice, which Defra published in 2004 and has since updated
- •Cinnabar caterpillars store the plant's alkaloids, and their black-and-orange stripes are a warning to birds
- •You are not obliged to remove ragwort from your land; Natural England can serve enforcement notices where it threatens grazing land or forage production
Drill it — 8 cards
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Sources
- The Wildlife Trusts — Common ragwort
- GOV.UK — Stop ragwort and other injurious weeds from spreading
- Defra — Code of Practice on How to Prevent the Spread of Ragwort