The Suitable Time and Common Methods for Grafting Pomegranate Trees
The pomegranate tree is a deciduous shrub or small tree, and is evergreen in the tropics. It is cultivated throughout both northern and southern China. Grafting pomegranate trees can convert inferior varieties into superior varieties with higher yields, better quality, and stronger resistance to stress. So, when is the suitable time to graft pomegranate trees? What grafting methods are there?
When is the suitable time to graft pomegranate trees?
Pomegranate trees are mostly grafted during the growing season. For the branch grafting method, the main phenological stage to grasp is the early bud-break stage, generally from late March to mid-April is the most suitable.
What grafting methods are there?
The most commonly used grafting methods for pomegranate trees are branch grafting methods such as bark grafting, cut grafting, and cleft grafting.
Bark grafting is carried out when the rootstock is sprouting and the bark is easy to peel. The method is: first, at the grafting position on the rootstock, choose a smooth, scar-free spot and saw it off vertically, then smooth the cut surface with a knife. Then, from the lower end of the scion, cut a large 3-4 cm long horse-ear-shaped cut surface on one side. Turn the scion over and cut a small triangular cut surface on the back side of the large cut surface, and use the knife edge to lightly scrape the rough bark on both sides of the large cut surface until the green shows. After cutting the scion, leave 2-4 buds (nodes) and cut it off. Next, on the rootstock, choose a straight cambium area and make a vertical cut perpendicular to the cross-section, reaching deep into the xylem, 2-3 cm long. After making the vertical cut, immediately use the knife edge to gently pry it open, so that the bark and xylem separate slightly, then align the scion with the cut, with the large cut surface facing the xylem, and slowly insert it until the large cut surface protrudes about 0.5 cm above the saw cut. Each rootstock cross-section can hold 2-4 scions. After inserting the scions, tie them starting from the lower end of the joint with plastic film tape until the scions and rootstock are tightly and securely bound.
Post-grafting management of pomegranate trees
1. Remove rootstock sprouts.
2. Check for survival and re-graft where needed. Check for survival 15 days after grafting. If all the scions above the joint are found to be completely wrinkled, blackened, and shriveled, it means the scions have died and need to be re-grafted.
3. Set up supports. The new branches that grow after survival are not yet firmly healed and are easily broken by wind. Therefore, when the new shoots are 15-20 cm long, tie some wooden sticks to the tree as supports (commonly known as tying a back).
4. Summer pruning. When the new shoots are 0-60 cm long, for new shoots being trained as scaffold branches (main and secondary branches), gently pull them according to the shaping requirements, tie them to the support sticks, and adjust them to the proper angle. For other branches, use methods such as bending, flattening, twisting, and pressing into mixed clusters to change the branches from upright growth to oblique, horizontal, or drooping states, so as to achieve both not affecting the growth of scaffold branches and forming more mixed buds for flowering and fruiting.
5. Prevent and control pests and diseases. At the early stage of pest occurrence, spray 20% fenvalerate 3000x solution. In areas where diseases are frequent, use 200x equal-amount Bordeaux mixture or 50% thiophanate-methyl wettable powder 800x solution for prevention.