Grafting onto cold hardy Annonas

[Annonaceae]

Quick question.   Annona cherimola, atemoya and some ornamental Annonas are more cold hardier.

My question is this, if I graft a Annona diversifolia, reticulata or others onto a cold hardy species will it then make the tropical species grafts cold hardy also?

The sap and or brix would be being delivered to the graft from the cold hardy root stock correct?

Could this work or be done?

[Guayaba]

Quick question.   Annona cherimola, atemoya and some ornamental Annonas are more cold hardier.

My question is this, if I graft a Annona diversifolia, reticulata or others onto a cold hardy species will it then make the tropical species grafts cold hardy also?

The sap and or brix would be being delivered to the graft from the cold hardy root stock correct?

Could this work or be done?

One of the Annona gurus will probably answer your question more thoroughly, but grafting A. diversifolia and A. reticulata onto Cherimoya root stock will not technically make the grafted portions more hardy to cold. Here in California, some A. diversifolia and A. reticulata can suffer from the cold and cool weather for several months and then die.  If grafted onto Cherimoya root stock, they tend to tolerate the cool conditions and cold wet soil better. The grafted portions are still subject to typical exposure to frost and freezes, so you can't grow A. diversifolia and A. reticulata grafted onto Cherimoya root stock in all regions that grow Cherimoya.

[Vernmented]

Quick question.   Annona cherimola, atemoya and some ornamental Annonas are more cold hardier.

My question is this, if I graft a Annona diversifolia, reticulata or others onto a cold hardy species will it then make the tropical species grafts cold hardy also?

The sap and or brix would be being delivered to the graft from the cold hardy root stock correct?

Could this work or be done?

One of the Annona gurus will probably answer your question more thoroughly, but grafting A. diversifolia and A. reticulata onto Cherimoya root stock will not technically make the grafted portions more hardy to cold. Here in California, some A. diversifolia and A. reticulata can suffer from the cold and cool weather for several months and then die.  If grafted onto Cherimoya root stock, they tend to tolerate the cool conditions and cold wet soil better. The grafted portions are still subject to typical exposure to frost and freezes, so you can't grow A. diversifolia and A. reticulata grafted onto Cherimoya root stock in all regions that grow Cherimoya.

That all sounds right to me but. I am no guru or have the experience to back it up but here is my take on it. There can be very minute genetic drift from rootstock scion but that wouldn't make much of a difference. I think of rootstock being important for cold hardiness due to the fact that the coldest air will be settled 18" to 24" above the soil line so you could plant on a mound and graft a little higher. Pick a rootstock that is hardier than the scion if freeze will be an issue. Alternately, you could use a less hardy rootstock better acclimated to your soil and then bury it or easily put some heat source like lights around it during the cold snaps but that wont help with sustained cold that drop the overall soil temperature for whole seasons like California vs Florida.

You could multigraft the less hardy species mid canopy in your tree and wrap some C9 xmas lights around them for the cold season and put them on a timer. It shouldn't be too expensive to give you a microclimate to scrape by if you aren't zone pushing too hard.

[Triloba Tracker]

If you want to get really cold hardy with Annonaceae, try using Asimina triloba rootstock 

I don't believe anyone has successfully grafted cherimola, squamosa, reticulata, etc onto pawpaw. I could be wrong.

[Delvi83]

I think it's difficult....but some evergreen species can be grafted on decidous species...(es. Orange on Trifoliate)...

So, someone should try to graft Annona c. on Asimina triloba....if it works, Cherymoya could be more cold-hardy (as Citrus grafted on P. trifoliate).

[marklee]

I doubt it would work because the rootstock goes into dormancy for so long. All of the other annonas need constant pushing.

[Guanabanus]

Grafting  a Tropical species onto a species that normally goes dormant doesn't sound like a problem:  the roots probably won't be harmed by being fed glucose from the leaves all year long.

It is when a deciduous species (goes dormant, leafless, in winter) is grafted onto a tropical evergreen root-stock, that root starvation can occur.  I let root-stock suckers grow to have leaves all winter.