In this video, This Old House landscape contractor Roger Cook and certified arborist Matt Foti show how to trim back a wildly overgrown willow.
1. Cut all the dead branches within reach using a pruning saw.
2. Execute an offset cut to trim larger branches: Make an undercut first into underside of branch about 18 inches from the tree trunk.
3. Then make a top cut about ½ inch beyond the undercut. Keep cutting until the branch falls to the ground.
4. Now trim what remains of the branch by cutting close to the trunk, but not into the branch collar.
5. Use a long-handled pole saw to trim branches that you can't reach with the pruning saw.
6. Use a chainsaw to cut branches that are rubbing against other branches.
7. Hire a professional arborist to trim branches that you can't reach from the ground.
8. Cut small-diameter branches from the canopy with a snap-cut pruner. Trim them high enough to allow you to comfortably walk beneath the tree.