- Latin synonym: Senecio jacobaea
- Name also: Common Ragwort
- Family: Daisy Family – Compositae, subfamily Asteroideae
(formerly Aster Family – Asteraceae)
- Growing form: Biennial or perennial herb. Rootstock short, erect.
- Height: 30–80 cm (12–32 in.). Stem branched, deep-grooved, sparsely hairy, reddish brown.
- Flower: Flowers form 15–25 mm (0.6–1 in.) wide, single flower-like capitula surrounded by involucral bracts. Capitulum flowers yellow, ray-florets tongue-like; disk florets tubular, small. Stamens 5. Gynoecium composed of 2 fused carpels. Involucre semi-spherical, involucral bracts 1 row, narrowly ovate, tapered, with membranous margins, virtually glabrous, green, dark-tipped; outer bracts at base of involucre 2–5, small, short, very narrow. Capitula quite dense, borne in a corymbose cluster.
- Leaves: Alternate, basal leaves and lower stem leaves short-stalked, upper stalkless, slightly amplexicaul. Basal leaves large, usually withered by flowering time. Blade 1–2 times pinnately lobed, underside usually sparsely hairy, lobes large-toothed, often roundish-tipped.
- Fruit: Round, ridged, glabrous–shortly haired, approx. 2 mm (0.8 in.) long achene with unbranched hairs on tip.
- Habitat: Roadsides, waste ground, railway embankments, ballast soil deposits, harbours, yards, meadows.
- Flowering time: July–September.
The genus Jacobaea is large and diverse, and members even grow in Northern Finland: at least 4 species grow wild in Finland. Ragwort is said to have received its scientific name after the apostle James, and indeed the plant doesn’t flower before St James’ Day at the end of July, while the older generic name Senecio comes from the Latin word senex, ’old man’, and refers to the silvery down of the achene. Ragwort spreads efficiently by means of its seeds, which are attached to downy hairs. It is easiest to find in areas where there isn’t so much fierce competition between plants. Ragwort originally arrived in Finland in sailing boats’ ballast soil deposits and still grows around the harbour areas of many coastal towns around the Gulfs of Finland and Bothnia. This rare established alien has also spread around the coastal area of the Gulf of Finland to roadsides and railway yards. It occasionally grows as far north as Kemi on the Lapland border and in Suomussalmi to the east.
Ragwort was cultivated in Finland alongside many other promising new useful plants during the Age of Utility at the end of the 18th century. It was used at that time to help alleviate stomach pains, for intestinal purges, and to arrest bleeding. The saint that ragwort is named after protected horses, and they were also experimentally medicated with broth made from the herb. Grazing animals do not usually eat Senecio plants, and with good reason: like its relatives, ragwort is poisonous, so it’s not advisable to experiment with it as a medicine. This abundantly-flowering plant is on the other hand a beautiful addition to the garden. It also has a place in the yards of wildlife-lovers: it attracts butterflies and other insects to eat its nectar, and many birds also like to eat its downy seeds.
Of the four Senecio plants on this site, ragwort is the finest. Having said that, Jacobea cannabifolia, a native of Siberia that bears a strong resemblance to hemp, has in recent years inched its way out of the flower bed and into the wild. It is almost 2 metres tall, and could be the next foreign species to attract attention in Finland.
Jacobaea aquatica (Senecio aquaticus)
Biennial marsh ragwort resembles quite much ragwort. In Finland marsh ragwort is quite rare species on shores and damp locations. The difference between these two species can be seen in basal leaves, which are lobeless with marsh ragwort (pinnately lobed with ragwort and when flowering, ragwort has no basal leaves). Marsh ragwort has basal leaves during whole season.
Jacobea cannabifolia (Senecio cannabifolius)
NOT TRANSLATED YET. Siperiasta kotoisin oleva, lehdiltään hieman hamppua muistuttava hamppuvillakko on sekin viime vuosina hivuttautunut paikoin kukkapenkeistä luontoomme. Jopa kaksimetriseksi kasvavana se saattaa olla seuraavia laajaa huomiota herättäviä muukalaislajeja luonnossamme. Nyt hamppuvillakko luokitellaan tarkkailtavaksi tai paikallisesti haitalliseksi vieraslajiksi.