Detailed Explanation and Key Operation Points of Grafting Osmanthus onto Fringetree
The fringetree (Chionanthus retusus) is a deciduous shrub or small tree, with a flowering period from April to June and a fruit ripening period from September to October. It is not demanding regarding soil and can adapt to neutral, slightly acidic, and slightly alkaline soils. Grafting osmanthus onto fringetree has strong compatibility and grows well. Osmanthus bonsai cultivated from fringetree rootstocks can be placed in the home. The best time for grafting is usually when the fringetree begins to sprout.
Cut Grafting Method
When grafting, cut the rootstock at an appropriate position, choose the smoother side of the bark, and make a vertical downward cut slightly into the xylem, with the cut 2 cm to 3 cm deep. Cut the scion into a 2 to 3 cm long slanted surface, and on the opposite side cut another short slanted surface of 1 cm, while retaining 2 to 3 opposite buds, and cut the branch crosswise. Immediately insert the scion into the rootstock so that the cambium layers of both are closely aligned.
For large rootstocks, several scions can be grafted. After inserting the scions, immediately bind and fix them with plastic film strips, and cover with a small plastic bag to retain moisture and warmth.
Side Grafting Method
Side grafting is a branch grafting method that does not cut off the rootstock crown. When grafting, at an appropriate position on the rootstock, make a slanted cut into the rootstock at an angle of 20 to 30 degrees, reaching 1/3 to 1/2 of the rootstock diameter. Then cut the lower end of the scion on both sides into slanted surfaces of 1 cm to 2 cm each, retain 2 to 3 opposite buds, insert the scion into the rootstock cut, align it with the cambium on one side of the rootstock, and bind with plastic film strips to retain moisture and warmth.
Cleft Grafting Method
When grafting, cut the rootstock at a certain height into a flat surface, then use a cleft grafting knife to split vertically down the center of the rootstock cut surface to a depth of 4 cm to 5 cm, then insert the back of the knife into the cut to open it. Select 2-year-old branches with 4 to 5 opposite buds as scions, cut both sides into equal wedge shapes, then insert the scion into the rootstock cut so that the cambium layers of both are closely aligned, and bind firmly with plastic film strips, while covering with a plastic bag and tying it tightly to retain moisture and warmth.
Bark Grafting Method
When the sap of the fringetree has begun to flow and the bark is easy to peel. First, cut a 2 cm to 3 cm long slanted surface on the back side of the scion 1 cm to 2 cm below the bud, then cut a small slanted surface about 0.6 cm long at the tip of the back of the slanted surface. Then cut and smooth the rootstock at the required position, then choose a smooth spot on the rootstock bark and make a vertical cut from top to bottom, deep to the xylem, about 1.5 cm long, gently pry the bark open along the cut to both sides, and insert the scion.
If the rootstock is thick, several scions can be grafted. After the scions are inserted, bind and fix them with plastic film strips, then cover with a plastic bag to retain warmth and moisture.
Approach Grafting Method
From May to July each year, cut both the fringetree and osmanthus at an appropriate height to remove 5 cm to 10 cm, making two approach grafting slanted cuts reaching 1/4 to 1/3 of the trunk diameter, align the cambium layers, and bind well with plastic film strips. One month after approach grafting (20 days at the fastest), cut off the lower part of the scion and the upper part of the rootstock.