Existing vines are candidates for grafting if the cultivar is not economical or not appropriate for the site. The vines to be grafted must be healthy and vigorous, without disease or insects, and relatively young. Scion wood collection is the same as for taking cuttings. The scion is taken while dormant for most types of grafting; however, actively growing tissue can be used in some cases. There are several types of grafts that can be used, including:
- Cleft grafts
- Bark grafts
- Whip grafts
- Budded grafts
- Green growing bench grafts
The cleft grafting technique.bark
must be "slipping" for this graft to work, so timing can vary from rootstock to rootstock. The scion must be dormant. The bark grafting process is:
Budding.leaf blade, leaving only the petiole intact, which acts as a handle.
- Select the vine and cut off the top.
- Prepare the scion by cutting a pattern into the basal end.
- Make matching pattern cuts on the rootstock.
- Insert scion and secure it to the rootstock with a grafting band or tape.
- Cover the area and seal the cut with grafting wax.
Shave the bud off the budwood. You only need a small sliver of wood.
On the rootstock, make a vertical cut to separate the bark from the cambium, then make a perpendicular cut at the top of the vertical cut to form a "T."
Carefully peel back the bark to expose the pocket for the bud shield.
Slide the bud shield into the open pocket and trim off the top if needed.
Wrap tightly with grafting tape, but leave the bud exposed.
After the healing process starts and you observe growth, you can remove the rootstock that was left above the budded area.
There is a rapid graft propagation technique where the callused graft is rooted under mist for 30 days, grown in a greenhouse for 30 days, conditioned in a lath house for 30 days and planted in the vineyard in mid to late spring (May, in northern areas). Vines from this system are called green growing bench grafts. Summer temperatures, sunlight, and low humidity can make green growing bench grafts very difficult to establish.