This was originally published as Leesburg AREC Research Rreport LBG 82-4

Grafting Bunch Grapes

By J. A. Mortensen, IFAS

Agricultural Research Education Center, Leesburg

December 9, 1982

Of  the  bunch  grape  varieties  resistant  to  Pierce's  disease,  the  following  Perform best if grafted on a nematode-resistant rootstock:  Stover, Conquistador, Black Spanish and Roucaneuf.

Grafting is best done at the latter end of the dormant season, usually mid-February to mid-March.  The rootstock should be cut off with a saw or sharp piece knife; larger stumps may be split with a grafting tool or wide chisel.  Rootstocks grown in pots can be cut off and split while still in the pot.  Make the split about 1 1/2 inches deep, and avoid going deeper.

The budwood for scions should be chosen from healthy vines.  A graft scion should be from 5 to 8 inches long with 2 or more buds and 1/4” – 3/8” in diameter.  The portion of the section to be inserted in the cleft should be cut carefully to a long, tapering wedge, preferably slightly thicker on one side.  The wedge cut should be started just below the basal bud on both sides.  Usually only one scion should be inserted carefully onto the cleft so that the cambium on its thicker edge and that of the stock coincide.  The pressure of a large stump may hold a scion securely; small stumps should be tied firmly with raffia or soft string.

Grafts are mounded with soil to prevent drying of the scion.  To protect the soil cover form erosion by wind and rain, a half-gallon milk carton (cut in half) may be placed over the graft and filled with clean, moist builder's sand up to the top bud of the scion.  During dry periods, water once a week or more often as needed.  The grafted vine should be trained to a single shoot on a stout permanent stake attached to the trellis wire.  With potted rootstocks, make sure stake extends deeply enough into the pot that it won't fall over.  The milk cartons should be removed after scion growth exceeds 15 inches up the stake, and string ties should be removed to prevent girdling.