Good news—> Raintree is now offering Gisela 6 cherry rootstock for sale.
Here’s what they say:
Raintree offers its cherries on Gisela rootstocks however because of patent restrictions we could not sell the Gisela rootstocks. Now Gisela 6 rootstock is available to the home gardener. Rootstocks are in small pots and many are about 3/16 inch in size, suitable for summer budding but perhaps too small for immediate grafting. USDA Zones 4-9. $6.50