Certain scion and rootstock combinations show an incompatibility
reaction, which may appear shortly after grafting or may
take 10 to 20 years to develop. An example of delayed incompatibility
is bud union crease. A crease or fold forms at the bud union
and, with increasing overgrowth, results in a slow girdling
of the tree.
When planting or replanting, avoid susceptible combinations. For example, 'Frost' nucellar navel on
trifoliate orange, lemon on 'Cleopatra' mandarin, 'Eureka' lemon or 'Satsuma' mandarin on 'Troyer', and
certain scion lines on sour orange develop bud union overgrowths. For more information, contact your
local extension office.
forming at bud union