How to Graft Evergreens
Grafting is a popular way to propagate trees, especially fruit trees. However, it also a technique that is performed on other deciduous trees as well as evergreens so that trees that might not be growing well can thrive. It is sometimes easier than starting fresh from seeds. Grafting is when you take a branch of one tree and attach it to another to grow. Evergreens should be grafted in winter during their dormant season, but not when the trees are frozen. The type of graft best used for evergreens is the slide veneer graft.
Prepare your rootstock--the evergreen onto which you will grafting the scion (new branch). Use a grafting tool to cut approximately a 2-inch slice down the side of the stem, just above the soil. This slice should be slightly slanted inward to reveal the tissue inside the tree. Cut the bottom of the slice to remove the wedge from the tree.
Prepare your scion. Choose a branch from a second evergreen. It should be at least a year old and healthy. It should be smaller than the rootstock. Slice the bottom of the scion to match the slice in the rootstock. The goal is to a make the rootstock and scion slices fit together like a puzzle. It may take some practice.
Piece the scion and rootstock together and wrap them in twine that has been soaked in grafting wax. The twine should be tight enough to hold, but not too tight that it punctures the tree. Unlike other grafts, do not seal the exposed wood tissues with grafting wax when grafting evergreens in this manner.
Keep the grafted tree in a greenhouse if possible, planted in well draining soil. Temperatures that fluctuate greatly will cause the graft to fail. Temperatures should be kept at around 60 degrees Fahrenheit at night and a bit warmer during the day. Keep the tree slightly moist, but not overwatered. Mist the tree every few days.