North American Fruit Explorers mailing list at ibiblio

[Kevin Bradley <kbradley@ttlc.net>]

You can still graft onto rootstocks that have come out of dormancy as  long 
as the  scions are still dormant. If the rootstocks have gone too long 
without any buds leafing out though it can lower your chances of success, 
in my experience, if I recall. If you whip and tongue grafted earlier you 
can do another whip and tongue graft lower on those that didn't take but it 
would be much better to use new rootstocks. You can also chip bud using 
dormant scions but my experience has been weak after- growth. I don't like 
re- grafting the same rootstocks in the same year, but I have done it with 
some success.
I have kept scions dormant at about 31 degrees up into June. (I have also 
frozen them and kept them into July. Freezing them is very risky though, 
you probably have to do it when they are in primary dormancy, in the late 
fall, and freeze them in a large amount of water with no contact with air 
or the sides of the container.)
As far as apple and pear and plum you can graft on dormant roots, apricots 
and peach actually do better if the rootstock has begun growth. You can 
even grow out some suckers from the peach and apricot rootstocks and whip 
graft them to your dormant scions, that is if you can keep your scions 
dormant that long. You should protect the new apricot and peach grafts with 
a plastic cover and slowly allow them to harden off once the grafts have 
taken. Pears and apples will callus at low temps from the high thirites and 
above, 50 degrees being ideal in my opinion. Apricots callus best in the 
upper fifties and plums in the seventies.  Peaches alos I believe in the 
seventies and even eighties.
Good luck
Kevin B.