Our Damson Plum Tree has some Black knot infection that we have been keeping somewhat under control by cutting out the knots this summer. This tree is overgrown with branches trailing down to the ground so we are not concerned about losing a lot of fruit next year. Can we prune this fall prior to the winter or is it safer to leave the pruning to early spring or late winter prior to growth? I understand the steps we have to take to try to save the tree with regard to the black knot it is just that I am unsure as to when would be the best time to do a severe pruning. Thanks for any input.