Hedera helix is an evergreen climbing plant, growing to 20–30 m (66–98 ft) high where suitable surfaces (trees, cliffs, walls) are available, and also growing as groundcover where no vertical surfaces occur. It climbs by means of aerial rootlets with matted pads which cling strongly to the substrate. The ability to climb on surfaces varies with the plants variety and other factors: Hedera helix prefers non-reflective, darker and rough surfaces with near-neutral pH. It generally thrives in a wide range of soil pH with 6.5 being ideal, prefers moist, shady locations and avoids exposure to direct sunlight, the latter promoting drying out in winter.
The leaves are alternate, 50–100 mm (2–4 in) long, with a 15–20 mm (0.6–0.8 in) petiole; they are of two types, with palmately five-lobed juvenile leaves on creeping and climbing stems, and unlobed cordate adult leaves on fertile flowering stems exposed to full sun, usually high in the crowns of trees or the top of rock faces.
The flowers are produced from late summer until late autumn, individually small, in 3-to-5 cm-diameter (1.2-to-2.0 in) umbels, greenish-yellow, and very rich in nectar, an important late autumn food source for bees and other insects.
The fruit are purple-black to orange-yellow berries 6–8 mm (0.2–0.3 in) in diameter, ripening in late winter,and are an important food for many birds, though somewhat poisonous to humans.
It ranges from Ireland northeast to southern Scandinavia, south to Portugal, and east to Ukraine and Iran and northern Turkey.
Ivy is widely cultivated as an ornamental plant. Within its native range, the species is greatly valued for attracting wildlife. The flowers are visited by over 70 species of nectar-feeding insects, and the berries eaten by at least 16 species of birds. The foliage provides dense evergreen shelter, and is also browsed by deer.
Ivy extracts are part of current cough medicines.