The goat willow (Salix caprea) is the European cousin of the native pussy willow (Salix discolor), and sometimes goes by the more continental moniker of French or European pussy willow. Suitable for U.S. Department of Agriculture plant hardiness zones 4 through 8, as is native pussy willow, goat willow grows up to 15 feet tall as an upright multistemmed shrub, or to 8 feet as the weeping Kilmarnock willow (Salix caprea "Pendula"). The 2-inch catkins on male plants are the main attraction -- kids love running their fingers over the soft buds that appear the week before they leaf out, or use them yourself in flower arrangements. Annual pruning keeps the fuzzy catkins coming.
Spray the blades of your pruners and loppers with a household antiseptic cleaner, and wipe them dry with paper towels. This decreases the chance that the tools could carry a damaging fungus or disease to your goat willow.
Cut all stems of an upright goat willow down to within 6 inches of the ground every one to five years with loppers or hand pruners to keep the plant's size in check and to ensure a yearly show of catkin-covered stems. Prune immediately after the catkins start to expand into feathery looking seeds, but before leaves emerge. New growth will emerge and leaf out over the spring and summer, and set new buds in the fall.
Cut one-third of the oldest, tallest stems back to the ground each year with loppers as catkins fade if you don't want to leave a temporary gap in your landscape.
Shorten some or all of the branches coming from the crown of a weeping Kilmarnock goat willow with hand pruners or loppers just after catkins start to fade, several inches above the crown of the tree. This is the point where the upright trunk is grafted to the weeping top of the tree. You'll usually see a swollen knot at this point. Make cuts just above a leaf bud pointing in the direction that you want new shoots to grow. These heading cuts help thicken the crown, which can look sparse.
Cut back weeping stems that are near the ground by trimming them up to the next side shoot. Cutting weeping branches off at one length, like a toddler's bangs, looks unnatural and encourages multiple branches to sprout from the cuts, ruining the lines of the plant.
Remove one-third of the oldest, longest stems each year after blooming, or cut the entire crown back every one to five years for the best display of catkins.