- Name also: Yellow Oxeye, Yellow Ox-eye, Heartleaf Ox-eye
- Family: Daisy Family – Compositae, subfamily Asteroideae
(formerly Aster Family – Asteraceae)
- Growing form: Perennial herb.
- Height: 60–200 cm (25–80 in.). Stem finely haired, green–violet, violet–dark reddish brown. Strongly scented.
- Flower: Flowers form 5–7 cm (2–3 in.) wide, single flower-like capitula surrounded by involucral bracts. Capitulum’s ray-florets yellowish orange, tongue-like; disk florets brownish yellow, tubular, small. Stamens 5. Gynoecium composed of 2 fused carpels. Involucral bracts overlapping in many rows, outer ones leafy, ovate, recurved, hairy; inner ones wide. Capitula borne in a lax corymbose cluster.
- Leaves: Alternate, lower stalked, upper stalkless, almost amplexicaul. Blade lower down ovate, cordate based, 30–40 cm (12–16 in.) long, higher up widely elliptic, double-toothed, thin, rough underneath, almost glabrous on top.
- Fruit: Bristly, glabrous achene crowned by a fine membranous ring.
- Habitat: Around dwelling areas, yards, parks, banks, forest margins, shores. Ornamental, sometimes left over from old gardens and an escape.
- Flowering time: July–August.
Heartleaf oxeye is native to exotic areas: it is a feral plant that grows from the Carpathian Mountains to Asia Minor and the Caucasus. Its inflorescence certainly looks exotic too, like a dark yellow shining sun. At the end of the growing season it takes more than a little bit of green to impress the plant enthusiast, but heartleaf oxeye’s showy eruption never fails to impress. It begins to reveal its yellow-flowered inflorescence in July, and other yellow asters then begin to follow suit. Its large leaves provide an exuberant background for its large capitula.
Heartleaf oxeye has been mainly planted in Finland in old manor parks, drawing attention as a lone perennial or in small groups. The species was brought to Finland for the first time at the beginning of the 20th century, and it still survives in many places as a reminder of old gardens, and has sometimes spread to the wild. Heartleaf oxeye grows best in shady or semi-shady places where the earth is damp. This traditional ornamental plant could be ready to make a comeback in large gardens. It is a good choice for gardeners who want to attract butterflies: its large capitula provide a landing base for larger butterflies of the monarch and papilionoidea families, and beetles also gather in the flowers to eat its pollen.
Heartleaf oxeye resembles elecampane (Inula helenium), which is another large perennial, but it differs from elecampane in that its slightly cordate leaves have green undersides while elecampane’s long leaves have woolly undersides. Like heartleaf oxeye, this central Asian species grows wild around houses in southern and central parts of Finland, but it usually favours drier habitats.