Rich, what kind of plums are you going to get off of that tree ?
Colorado Blue Plums


I had to remove the plum tree since it was so badly infected, there was nothing left, if I cut all the infected branches off. I still have 6 plum trees around in all different parts of the yard. I trimmed all the affected branches as best as I could see/find. If it is caught early, it lessens the speed of spread. I know that eventually I will loose those trees also. I plan on transplanting some of the ground/root sprouts while small, into remote areas of yard, so they will grow, as replacements. I have some ideas I will try,, to see if I can stop the fungus from growing, once I spot a small nub. I am considering Neem oil, and possibly Laundry Bleach, and Peroxide. Not all at once, but experiment on separate knots. Was thinking of wrapping fungus with gauze, then wet down, then wrap with saran plastic wrap. Its worth a try. Not much to loose.
Maybe the heavy landscaping fabric would be the solution to Jim's problem.
Here is something I did, when I had some decorative hanging baskets.
They were made of a nice wire type frame, and inside, held a nest type basket. Not sure what the nest material was made of, looked like some type of hay like strands. Brown in color. The replacement nests were pricey, almost as much as new baskets, so I threw away the rotted nests. I lined the wire frame with some material I cut up from my retired Jeans. The material held the potting soil very well. Drained very well also. My flowers grew very well, and never encountered root rot, from over-watering. Jeans material lasted a couple years also, and was outdoors year round. I suppose nylon/polyester fabric would last even longer than cotton.

Yes, I do water my hanging flowers daily, unless it is raining. I also fertilize regularly.
Below is a funny pix,
and it is not where I got my inspiration to use my retired jeans as pot liner. It is no different than peeps growing potatoes in feed bags.