Keep them out of water to preserve the furry catkin. ... If left in water they will grow roots. The branches can then be popped into soil where they will grow rather easily.
Can you plant catkins?
Along with snowdrops and daffodils, catkins are regarded as a welcome sign of spring, so if you can't get out into the country as easily as you'd like, then grow them in your garden.
What is P * * * * willow?
Pussy willow is a name given to many of the smaller species of the genus Salix (willows and sallows) when their furry catkins are young in early spring. These species include (among many others): Goat willow or goat sallow (Salix caprea), a small tree native to northern Europe and northwest Asia.