I started a small patch of fruit trees back in 2022 which include FK, FS, and Dapple Dandy. I have encountered every single possible issue since I started this journey. From late frost, peach leaf curl and last year plum curculio and what I believe that perhaps was brown rot . This year I think I have black knot on my FS and also on Dapple Dandy. F.S. has not broken dormancy yet either. I’ve never grown a tree in my life so all this is new and even after reading and doing research I’d love some input from those more experienced growers. The black knot affecting both trees is minimal but the lesions are where the branches meet the trunk and of course they are the lower branches. I will have to butcher a bit into the trunk if I cut it no matter what. If i cut 5-6 inches below the lesion as it has been suggested, It will remove almost the whole tree. Should I even attempt to save the trees? Specially flavor supreme? The tree blooms like crazy around the end of february since i planted it back in 2022, but has never produced a fruit. This year it is still dormant, I cut into the tree in a few sections and it seems to be alive but no signs that it will wake up. Again should I attempt and save them or get them out and start fresh? I don’t want FK or my pluerry to get infected. Thank you.
FS is known to be a bit stingy setting on the east side of the country. Those trees are already there, so you might as well try butchering them. DD and FS both had black knot for me, but they were in easily cuttable locations. For the moment I still have DD, but I ditched FS last year. Black knot can be controlled, but limited fruit set is not tolerable. Santa Rosa is another that doesn’t seem to like the east coast.
I agree that you may as well try to save the trees affected by Black Knot. I had success with just carving out a small mass of knot on the main trunk of a plum tree; it healed over perfectly in a few years.
I would cut off the affected branches as close as possible to the trunk and then carve out any visible Black Knot on the trunk. Then keep inspecting those areas regularly and cut out any knot that develops as soon as possible.
The split branch junction in the lower photo doesn’t seem to be healing properly, and the narrow clamps holding it together are damaging the main trunk and the branch. I think that the tree would be better off if you cut that branch off completely and cleaned up the damaged area.
Carving out black knot with a very sharp knife (be careful) is the only effective treatment I know. chlorothalonil is widely suggested as being somewhat suppressive of new galls but I’ve not found it very useful. Scott swears by the blow torch method, but I don’t like that route either after trying it.
Black-knot pressure varies wildly, not just region to region but site to site, so take anyone’s advice with a grain of salt. Cut out the galls right to hard wood and beyond stained wood by an inch or so. Cut off the less vertical leader completely and remove those dangerous ties that will kill your tree by girdling it. You want a single trunk with scaffolds half the diameter of the trunk or less at point of attachment, at least as you are training the tree. Best way for me is to start with a central leader and after 3 years usually cut out the center of the tree and make it an open center. You can look all this stuff up.
Thanks everyone. I should have mentioned I am in Indianapolis. I think I will be removing the FS and attempt to save the DD. I tried to remove those clamps earlier this month but the split did not fuse together even though the trunk kept growing. I order an emerald beaut and a laroda plum that I will be replacing the tree with. Now, would it be safe to take scions from the FS or is it to risky due to the black knot?
You could also support the FS with a stake and gradually subdue it to give the other leader true dominance over time. You might also support both with stakes to have utter insurance the tree won’t split apart, or use a piece of wire between them secured with eye screws set directly into wood. But stakes would be more stable.
Ditch the FS variety, it is too stingy in many climates. I got maybe 20 plums in 15 years of growing it.
I would consider cutting off that tree below the split and grafting a variety you like on it. Several places sell wood, eg Fruitwood. Japanese plums are one of the most forgiving to graft so are a good starter if you have not yet grafted.
Re black knot it is totally containable, it just takes experience cutting out the knots. I blowtorch after cutting out as added insurance, a few cuts would re-infect the next year but not if torched.
For future reference the way I save a split like that is to connect the two limbs several feet higher with a cable. By putting it high you get many times the leverage. The cable should be as high as possible but before there’s major branching.
