- Name also: Common Sea-buckthorn
- Family: Oleaster Family – Elaeagnaceae
- Growing form and height: Shrub (or small tree when cultivated). 0.5–3 m (1.5–10 ft.).
- Flower: Small, without corolla. Male and female flowers on separate individuals. Male flower has two brownish sepals and four stamens, male inflorescence a catkin, borne in spring before emergence of leaves. Female flower has a two-lobed calyx and one carpel, female inflorescence small, axillary.
- Leaves: Alternate on annual shoot. Short-stalked or almost stalkless. Blade entire, 1–5 cm (0.4–2 in.) long, linear, greenish-grey above, underside silvery, covered with grey or rusty-brown scale-like hairs.
- Buds: Irregularly round, lumpy, shiny brown.
- Fruit: Thin-skinned, yellowish-orange, fleshy drupe-like pseudocarp. Seed deep brown, glossy.
- Habitat: Sandy seashores. Also an ornamental.
- Flowering time: May–June. Flowers before coming into leaf.
Sea buckthorn is a thorny shrub which forms dense thickets through suckering. It is dioecious and wind-pollinated. In Finland, it occurs in the Åland Islands and on the coast of Ostrobothnia. In the mountains of Central Europe it also grows in river valleys. Sea buckthorn is a typical pioneer species which spread to Finland right after the ice age following the melting ice cover. At that time it could also grow inland, but being a weak competitor it had to retreat to the coasts when closed vegetation developed. Sea buckthorn requires plenty of light. Like alders (Alnus spp.), it has the capability of fixing atmospheric nitrogen.
Berries which are rich in vitamin C are very valuable, but troublesome to gather from the thorny shrubs. However, it is not recommended to break twigs of wild sea buckthorns in order to collect the berries. Sea buckthorn is the county flower of Satakunta.