What month is suitable for grafting longan?
SummaryThe period from the Start of Spring to Qingming is a relatively good season for grafting longan, that is, around February to March. Grafting longan trees during this period not only gives a high success rate, but the successfully grafted longan trees can bloom and bear fruit the following spring. In fact, longan trees can also be grafted in summer and autumn, but the survival rate will be relatively low.
I. What month is longan grafting done
1. February to March is the best period for grafting longan. Grafting too early means low temperatures, and the plant's physiological metabolism, fluid flow, root system and branches and shoots are in a semi-dormant state.
2. If grafting is delayed, the scion consumes a large amount of nutrients due to sprouting new shoots and is baked and stuffy under high-temperature weather, and the time suitable for the scion and rootstock to heal is insufficient, which will affect the survival rate of longan.
II. Preparation before grafting longan
1. Shape and prune the longan 2-3 days in advance. This is especially true for vigorous trees, whose root water transport system is strong; sawing the tree in advance allows excess water in the tree to be discharged.
2. Leave 2-3 weaker-growing “balance branches” at the grafting site to channel the flow of water in the tree body and promote healing between the rootstock and scion.
3. The rootstocks selected when grafting longan should be evenly distributed around the tree. When the tree is strong and the fertilizer and water conditions are good, a small number of nurse branches may be appropriately retained.
4. Nurse branches generally retain about one quarter of the original tree canopy, so as to ease the imbalance of nutrients and water in the grafted tree. For nurse branches, it is best to keep middle branches.
5. The grafting positions on the whole tree should be kept at the same height as much as possible.
6. For dwarfed cultivation, on the premise that the rootstock diameter is suitable, low sawing should be carried out appropriately. Select rootstocks at the same branch grade; do not saw one grade higher.
7. For large branches or relatively large branches, first use a machete to cut off their branches and leaves before sawing the branch, to prevent the saw cut from tearing. The saw cut should be flat and perpendicular to the branch.
III. Selection of longan scions
1. For longan scions, select high-quality, representative mother trees as the source for collecting scions.
2. Then cut summer and autumn shoots from the middle and upper part of the tree canopy that grow robustly, have plump axillary buds and are free of pests and diseases, to serve as scions.
3. The cut shoots should have their leaves removed promptly and the scion sticks sorted out, then collected in a certain quantity for moisture-retention management.
4. Longan scions should be collected and grafted immediately, and at most should not exceed one week.
IV. Methods of grafting longan
1. Longan grafting should be carried out in the steps of shaping and fixing the tree form — cutting the rootstock — trimming the scion — inserting the scion bud — tying with film, and so on.
2. When grafting, choose a rootstock and scion that each have a flat, straight cut surface, to ensure that the inserted scion can be inserted tightly.
3. Cut the scion bud at a 45° angle below the bud eye, and on the opposite side make a straight cut into a straight flat surface 3-4 cm long reaching the cambium or slightly into the xylem, then cut it off about 1 cm above the bud eye.
4. When inserting, insert the scion bud downward and tightly, with the long straight cut surface facing inward and aligned with the rootstock cambium; if the sizes differ, align one side.
5. When tying, wrap the film from bottom to top to fully seal and bind the junction between the scion bud and the rootstock. At the bud eye, pull a single layer tight so it is thin but not broken. Only in this way can the scion bud smoothly emerge through the film.