osier

koripaju

pajunvitsa A kind of willow, (taxlink), growing in wet places in Europe and Asia, and introduced into North America. It is considered the best of the willows for basket work. The name is sometimes given to any kind of willow.
One of the long, pliable twigs of this plant, or of other similar plants.
1952, L.F. Salzman, Building in England, p. 188:

Wattling consists of a row of upright stakes the spaces between which are more or less filled by interweaving small branches, hazel rods, osiers, reeds, thin strips of wood, or other pliant material.