Walnut trees are usually grafted in spring, and the best grafting time is between mid-April and late April, which is mainly related to temperature. If the temperature is too low, inappropriate temperature will affect the survival rate of plants. If the temperature is too high, the wounds of plants will not heal easily in high temperature environment, and bacteria will be infected, thus affecting the growth of plants.
Before grafting, strong iron walnut or wild walnut should be selected as grafting rootstock. This kind of tree has good growth, strong drought resistance, cold resistance and disease resistance, strong tree body and strong adaptability, which can improve the survival rate of plants. Trees over 5 years old can be selected as rootstocks, and then disease-free treetops on healthy mother plants can be selected as scions.
Cuttings can be used to cut a small mouth under the bud of the scion. To cut the white wooden part of the tree, the incision can be coated with rooting water. Flatten the cross section of rhizome and cut it vertically to the depth of white wood. After cutting, the cut of the scion can be close to the wooden part of the rootstock, and then tied tightly with plastic strips.
Matters needing attention in walnut tree grafting:
Walnut field grafting uses green branch scions of walnut trees, which are picked nearby and grafted while picking. If you need to transport or store the scion for a short time, you must do a good job of moisturizing. The grafting site should be selected on walnut branches under 3 years old. The grafting site is too thick and the cortex is too thick, which affects the survival rate.
When grafting walnut trees with large rootstocks, they should be reshaped before grafting. Complete walnut leaf buds or mixed buds must be selected for bud grafting, and male flower buds cannot be used as scions. Using male buds as scions generally cannot germinate in the same year.