Chestnut Tree Propagation Methods
The American chestnut tree is making a comeback thanks to new strains that resist the infamous chestnut blight, which nearly eliminated this towering tree by the mid-20th century. You can propagate a chestnut tree by seeds, grafts or cuttings, as described below, and provide food for many types of wildlife.
Propagate Chestnut Trees from Seeds
Obtain healthy chestnuts in the fall from a surviving mature tree over 10 years old, or from a garden center. Store them in slightly damp peat moss, place them in the refrigerator and plant them in March or April. Choose a location with full sunlight and slightly dry, well-drained soil, that is high in phosphorus. This will promote flower development of your new young tree after 2 years, and ensure a steady supply of chestnut burs and chestnuts for more trees in the future. Separate the nuts off the growing seedlings to protect them from hungry squirrels.
Propagate Chestnut Trees from Cuttings
Propagating is the most difficult way to grow a new chestnut tree. You need to find a tree with strong greenwood, and cut the shoots from it in late spring, after flowering. Cut a branch about 10 inches long, and treat the exposed inner bark of the tip with the root enzyme indole 3 butyric acid. Plant in a large pot with peat moss and vermiculite. Water well, when soil has dried visibly on top. Transplant into a permanent location only after it has shown steady growth indoors for 3 months and has developed a definite taproot.
Propagate Chestnut Trees from Grafts
Chestnut trees thrive when grafted, resisting chestnut blight to a high degree. You will need to obtain live slender stems, called scions, from chestnut trees that have developed blight resistance. Get these before the flower buds open in early March. Store these in the refrigerator for a few weeks until the tree buds begin to open outdoors. One of these buds will become the graft site, in the technique known as whip grafting. Cut off a very slender root stock branch 12 inches above the junction, from the tree receiving the graft. Choose a branch up to 1/4 inch in diameter, and cut on a long, slight angle to expose plenty of inner bark. Split the graft-receiving branch by cutting shallowly into the side of the angled cut. Find a scion branch about the same size as the recipient, and trim its tip with the same angled cut you made on the recipient branch. Split the scion the same way as the receiving branch. Interlock the scion with the receiving branch at the splits so that the inner bark sections of each are in contact. Bind the junction snugly with black electrical tape, and cover the join thickly with a grafting compound. Provide a feeding of balanced fertilizer in a 20-20-20 blend and water regularly. Once the scion has established itself and is producing its own flowers and leaves, release the joint from the electrical tape. After 2 years, take cuttings directly from the scion to produce healthy, blight-resistant saplings. These trees will in turn produce healthy chestnut trees and seeds.