- Variations: Ssp. repens var. repens and ssp. repens var. argentea
- Family: Willow Family – Salicaceae
- Growing form and height: Shrub or dwarf shrub. 10–70 cm (4–30 in.).
- Flower: Male and female flowers on separate plants. Inflorescence a small, almost globose catkin on a short, leaved stalk. Individual flowers in axils of catkin scales, small, lacking perianth. Catkin scales narrow, silky-hairy, brownish or reddish. Stamens 2, filaments hairless, anthers yellow. Pistil formed from 2 fused carpels, ovary long-stalked, hairless or hairy.
- Leaves: Often opposite. Short-stalked, lacking stipules. Blade 1.5–3 cm (0.6–1.2 in.) long, oblanceolate, often with bent apex, green and eventually hairless above, underside densely covered in smooth, shiny hairs, margins glandular, rolled under. Vein pairs 4–8.
- Buds: Globose, reddish, hairless or hairy.
- Fruit: Hairless or hairy capsule. Seeds bar-like, densely plumed.
- Habitat: Sandy shores, mire margins, mires and mire meadows with thin peat layer, depressions in sandy pine woodland.
- Flowering time: May. Flowers before coming into leaf.
Willows are insect-pollinated, sympodially growing, dioecious trees, shrubs, or dwarf shrubs. Their buds have a single protective scale, and their leaves are entire and stipulate. The inflorescence is a catkin which falls off in one piece.
Creeping willow is a low shrub or creeping dwarf shrub which has delicate twigs bearing flowers before coming into leaf. Its distribution is western. Creeping willow is usually regarded as a group of two variations of which var. repens is more common. Hybrids between willow species are common. Creeping willow typically crossbreed with goat willow (S. caprea) and downy willow (S. lapponum).
Salix repens ssp. rosmarinifolia (also Salix rosmarinifolia)
NOT TRANSLATED YET. Kapealehtipaju luokitellaan lähteestä riippuen omaksi lajikseen (mm. The Plant List) tai hanhenpajun alalajiksi. Se on selvästi muita hanhenpajuja korkeampi, jopa 1,5 m ja pystyhaarainen. Selkein erottava tekijä on lehtilavan muoto; niin kuin nimikin sanoo, lapa on muodoltaan kapea, tarkemmin kapeansuikea ja ehytlaitainen. Suonipareja on 10–12. Lehdet ovat yleensä korvakkeettomia. (A willow species in Finland with still narrower leaves is osier, S. viminalis.)