given you’ve invested time and effort in this tree already. Why not give NOGALL a try to see if it helps? perhaps you can root drench now and dig it out during dormant season and soak the roots with NOGALL.
Just checked and my cot-n-candy aprium and flavor grenade pluot are also on Citation.
I can’t find NOGALL on Amazon.
If you have a link please post.
Thanks
From my POV it does not matter what you do, You’re fighting a losing battle. With over 50+ years experience, none of those plants you’re trying will do well in these deep south locations. Flavor Grenade will do ok for a little while, then bacterial diseases will wipe it out too. However, FG does quite well grafted to peach on a ongoing basis. I graft a few new ones every year.
I am planning on getting some Lovell (peach) rootstock and hopefully some adara/puente scions to root and graft.
Assuming my FG survives until next year I may graft my own tree onto the Lovell or adara, whatever is compatible.
Adara is said to be compatible with all Japanese plums and FG is mostly plum parentage.