Frost on the the green growth of the scion isn’t bad. I have several peach trees I budded last fall. I moved them to the orchard and they are pushing green out of the buds. It has to get pretty cold to freeze that new growth off, so the growth itself is OK.
The problem is that cooler temps inhibit callusing, which is essential for grafts to take. Pomes callus at lower temps than stone fruits, but even pomes callus faster at higher temps.
I have young apple rootstock pushing some leaf growth now (older trees are still dormant). Nevertheless I’ll wait till I’m a bit more comfortable with the temps before I start grafting them. I wait till temps are in the 80s before I start grafting peaches.
Probably mid April for pomes. I’ll wait till well into May before I start grafting peaches.
I can imagine that most professional grafters can’t wait for the perfect conditions because they have too many jobs. From what I’ve seen, most will use black materials attract solar heat during cooler weather and reflective materials if they anticipate high temperatures.
Here is the my 4 yrs old Lanti Jululi Asian pear bark grafted on a Home Depot Cleveland Flowering pear rootstock from the end of season clearance. I found that Callery rootstock tend to have a dwarfin affect on the grafted variety.
I just googled Lanti Jululi and get no results Other than the garden Web thread. Are there any good sites that have information on it and are there scions available? Sounds delicious.
Only Scott and I got it from the USDA Corvallis free scions and just have to pay for FedEx Shipping. My already starting to leafed out. You can Google Lanti Jululi USDA Corvallis. There are lots of European, Asian, and Hybrids from the USDA.
Something stumps me when trying to apply for plant material there.I think the last time,the question was something about what organization I belonged to.I didn’t know what to answer,so I stopped there. Brady
Here in the northern zone 5, I would use black up until summer. In summer I would avoid dark colors. I think the reflective material is only used in the southern latitudes.
I’m not sure about the bark temps at which actual tissue damage could occur. It would be nice to know. It might be that higher heat simply dries out the tissue faster. I’m sure temperature issues also depend on the species being grafted.
I am going to bark graft some of the pears and apples scions this weekend. The weather in the next two weeks will be in the upper 60’s and 70’s. I think your MIssouri weather should be warmer than mine. You should be OK to bark graft your giant pear tree.