persimmon grafting

DIFFICULTY: medium - Persimmon wood is harder to cut than apple and pear.  Proper timing is critical.

TIMING: Graft when fully leafed out. In zone 7a I graft outdoors in May and June.  This is later than other species like apple and pear, which staggers the grafting season. 
 
CALLUS TEMPERATURE: 70-80F  If grafting outdoors, night time temperatures are ideally not much bellow 70F.
 
TECHNIQUE: Whip and tongue graft when scion matches the diameter of rootstock.  Bark graft when rootstock is much larger than scion material.  Many methods will work, this is my strategy.

ROOTSTOCK: I graft onto our native american persimmon (Diospyros virginiana) either field grafting wild established trees, or grafting potted seedlings grown from seed of improved cultivars.  Diospyros virginiana is graft compatible with american, kaki, and hybrid persimmons. For those living in warmer growing zones, Diospyros lotus can be used as rootstock for american, kaki, and hybrids. Diospyros kaki rootstock can have incompatibility with american persimmon.  
 
KAKI SUDDEN DEATH SYNDROME: Sometimes when grafting Asian or hybrid persimmon onto American persimmon rootstock the graft will heal and grow, then die.  It typically occurs shortly after the scion's initial growth, but there are reports that it can occur years after establishment.  If a rootstock does it once, it will likely do it again, suggesting not all American rootstocks are compatible with kaki genetics.  There are reports that younger rootstocks more reliably accept kaki grafts than older established ones.  Some people suggest grafting onto American x Asian hybrid rootstocks to reduce SDS, but there has been mixed success.  One theory is that SDS is caused by Xylella fastidiosa bacteria spread by insects and the incompatible rootstocks are simply infected.  In that case deep nutrition and ecosystem health may be a primary strategy in reducing SDS.  It's possible that SDS is caused by both the bateria pathogen and graft incompatibility of certain American rootstocks with kaki persimmon.  
 
NOTES: Reports of persimmon psylla killing young grafts.  If these small insects are infesting young grafts, may be best to cover with reemay cloth or similar fabric until the graft has established growth.