- Name also: Mountain Cornflower, Bachelor’s Button, Montane Knapweed, Mountain Bluet
- Family: Daisy Family – Compositae, subfamily Carduoideae
(formerly Aster Family – Asteraceae)
- Growing form: Perennial herb. Rootstock creeping. Forms stands.
- Height: 30–80 cm (12–32 in.). Stem usually unbranched, winged, sparsely hairy.
- Flower: Flowers form 5–8 cm (2–3.2 in.) wide, single flower-like capitula surrounded by involucral bracts. Capitulum ray-florets neuter, dark blue (sometimes light red or white), obliquely funnel-shaped, lobed tip; disk florets purple, tubular. Stamens 5. Gynoecium composed of 2 fused carpels. Involucre oval-round, involucral bracts overlap in many rows, lime green, tip dark brown, triangular–ovate, pinnatifid or ragged-toothed. Several capitula, individually terminating each stem.
- Leaves: Alternate, stalkless, decurrent, ascending oblique. Blade lanceolate, with entire margins, woolly underneath.
- Fruit: Flattish achene with very short bristles on tip.
- Habitat: Yards, roadsides, rubbish tips, broad-leaved forests. Ornamental, escape.
- Flowering time: Juny–August.
Perennial cornflower is originally native to central and southern European mountain meadows. It was originally used there as a medicinal plant, but here in Finland it is the most popular perennial in its genus and is an essential part of traditional garden flower beds. After having been cultivated for a long time as an ornamental, it has made itself at home here and there in southern and central Finland. The species spreads quite naturally by means of both its seeds and its creeping rootstock. Apart from the blue-flowered variety that predominates, there are also varieties with red, violet and white ray-florets, although these are rare in Finland. Perennial cornflower stays green throughout the winter and is able to gather strength while it is in bloom and also during the winter months when the trees have shed their leaves. This is why it is able to flower in relatively shady areas and can begin to bloom a little earlier than most other flowers in summer.
Perennial cornflower’s colour scheme of dark violet disk florets and dark blue ray-florets is similar to cornflower (C. cyanus), but perennial cornflower’s capitula usually terminate the stem singly, while cornflowers do so in number. Additionally, cornflower has clearly narrower leaves and is grey-haired. Recently this species, which has easily been overlooked as a weed and regarded as worthless, has found its place in the flower-bed as an ornamental alongside perennial cornflower.