hi!
unfortunately some of my rootstocks have cracks...
I think this is not due to general deep temperatures. over winter my citrus were covered by some kind of greenhouse, after winter everything was green and fine. it got warm inside, but not too much, plants seemed to break dormancy(no new shoots or buds visible).
after uncovering the citrus it got pretty cold again for two nights
the rootstocks are swingle, can cracks heal and be able to feed the grafted variety? the grafted varieties have no cracks, but major twig damage, they could be still alive.
thanks!