Although weeping willows can be propagated by cuttings and rooting, grafting can help you ensure that your weeping willow tree grows from a root stock more suited to your climate zone. Although weeping willow grafts are less common than for fruit trees, the general process and procedure is the same. A scion, or young branch, from a weeping willow is grafted to a sturdy root stock in the spring.
Make a 1 1/2 inch cut on the main trunk of the root cut starting from the outside of the root upward to create an angled cut with a sharp edge at the top.
Make a cut straight down through the middle of the trunk beginning halfway down the initial cut and ending at the base of the first cut. Cut, don't split, this second cut.
Make a matching cut on the scion, including the center tongue cut.
Slip the scion into the root stock, mating the tongue cuts for optimal contact between the scion and the root stock.
Wrap the graft tightly with grafting tape to help maintain contact.
Cover the graft and tape with grafting compound to seal the graft.
Remove the grafting tape and compound once the grafted portion of the tree has started to grow.