A Detailed Explanation of Seedling Grafting Methods and Techniques
Seedling grafting can use five methods: bud grafting, cleft grafting, approach grafting, side grafting, and cut grafting. Among them, bud grafting involves cutting the scion bud into a shield shape and cutting the rootstock into a T shape to insert the scion; cleft grafting is used for thicker rootstocks or when top grafting to change varieties; approach grafting means the rootstock and scion each have their own separate root systems during the grafting process; side grafting is grafting performed on the side of the rootstock; cut grafting involves cutting vertically down into the rootstock slightly into the woody part, and cutting the lower end of the scion into a slanted surface for grafting.
What are the methods and techniques for grafting seedlings?
1. Bud grafting: Bud grafting refers to a method of grafting using a bud with a cambium layer as the scion.
Bud grafting is generally carried out from July to September, usually using the "T" shaped shield bud insertion method, that is, the scion bud is cut into a shield shape, and the rootstock is cut into a T shape to insert the scion. When handling the rootstock, choose a smooth surface at the grafting site, preferably on the north side, make a horizontal cut deep enough to reach the xylem, then make a vertical cut downward from the incision to form a "T" shape, gently peel back the bark (including the xylem), insert the scion bud into the "T" shaped incision, and finally wrap with plastic film from bottom to top, leaving the bud eye exposed, tie a loose knot, and remove the tie immediately when the bud sprouts the following year. After completing the grafting, observe frequently; if the scion bud is found to have sprouted, promptly remove the wrapping film.
2. Cleft grafting: Also called split grafting, generally used for thicker osmanthus rootstocks or when top grafting to change varieties.
For rootstock treatment, note that the growing point and heart leaves should be removed. When grafting, cut the rootstock at a certain height, then use a cleft grafting knife to split vertically down the center of the rootstock cut surface, with the incision ideally 4 to 5 cm. For the scion, generally choose 2-year-old branches with 3 to 4 nodes, with a length of 10 cm being ideal. Cut both sides of the scion into equal wedge shapes, then insert 2 to 4 scions into the rootstock incision, ensuring the cambium layers of both are closely aligned, and bind firmly with plastic film, paying attention to covering the rootstock cut surface and the top of the scion with the film strip.
3. Approach grafting: Its characteristic is that the rootstock and scion each have their own separate root systems during the grafting process. Only after confirming that the scion can survive on the rootstock are the root systems separately cut. Approach grafting can generally be carried out from May to June. When approach grafting, take the mother plant branch serving as the scion and the mother plant branch serving as the rootstock, at the corresponding height, cut away 5 to 10 cm from each, leaving two approach grafting slant cuts deep enough to reach one-third to one-half of the trunk diameter, align the bark so that their cambium layers connect with each other, then bind firmly and securely with plastic film. After the graft has taken, the scion can be cut off from below the union.
4. Side grafting: A grafting method performed on the side of the rootstock.
When grafting, within 3 to 5 cm from the root of the rootstock, use a grafting knife to make a slanted cut into the rootstock at 20 to 30 degrees, reaching a depth of 1/3 to 1/2 of the rootstock diameter. Cut both sides of the lower end of the scion branch into a 1 to 2 cm double-sided wedge, retaining 1 to 2 pairs of buds. After cutting off the scion, insert it into the rootstock incision, align it with the cambium layer on one side of the rootstock, then bind the entire union with plastic film strip.
5. Cut grafting: When grafting, at 5 to 7 cm from the ground, cut off the rootstock and smooth the cut, then on the smoother side of the bark, cut vertically down slightly into the woody part, with the incision ideally 2 to 3 cm. The lower end of the scion needs to be cut into a 2 to 3 cm slant, and on the opposite side of the slant, make another short slanted cut of about 1 cm. The scion should retain one or two pairs of buds, and when cutting the branch, cut horizontally.