English walnut trees (Juglans regia) are attractive landscape trees that also offer a nut crop, making them a good choice for homeowners. A good tree might produce 100 lbs. of walnuts in a year, according to Oregon State University. These trees can pose a challenge in terms of pruning, since walnuts grow very tall. Prune a walnut tree every two or three years, and use a ladder or rent a mechanical pruning tower from a landscape rental service.
Wait until frost danger has passed in your area. Then check the tree's limbs for signs of dead, diseased or damaged branches. Dead branches don't move in the wind and feel brittle. Damaged or diseased wood bears physical blotches or discoloration.
Prepare a 1:10 solution of bleach to water in a bucket. Place all your pruning tools in this solution.
Cut off dead, diseased or damaged wood at its base. Use the lopping shears for growth larger than 3/4 inch in diameter and anvil pruners for smaller growth. Use a hand saw for large limbs that your pruners cannot cut through. In between each cut, resanitize your tools in the bleach solution.
Cut back long branches to a Y intersection, 2 to 4 feet from the tip of the branch. This invigorates the old wood to produce new growth. Perform this step only every three to five years.
Remove any downward-growing wood or branches that cross other branches by cutting them off at the base with your pruning tools. Also cut off any limbs that grow too close to vertical or grow toward the tree's trunk. All of this wood shades the tree, crowds the canopy and is not strong wood.
Thin out the walnut canopy by removing weak or old branches from the center of the tree. Choose branches that you've observed to be less productive during past growing seasons.