Q. How drastic a pruning will pyracantha tolerate? I’ve kept after mine for ten years, but it’s encroaching on a walkway and up onto the garage roof, plus the interior is very sparse. Michael Farley – DuPont, WA
A. That all depends on what you mean by drastic. If you mean cutting it back to the base then I would have to say no it is not tolerant. Drastic pruning is not recommended for Firethorns (Pyracantha spp.). But since you have been “after” yours for 10 years and it is encroaching on your walkway then you could probably have pruned it more than you have in the past. As with many other shrubs I suggest that in any given year you do not prune more than 1/3 of the plant. Then after one season you can see how the shrub responds to the pruning and continue until you have it in a shape and size that is suitable for the area it is located. Since the beautiful orange, red or yellow berries are one of the reasons we grow Firethorn then you may also want to consider the fact that the flowers and fruit form on previous season’s wood. If you goal is to maximize fruiting then the best time to prune is right after they finish flowering so that any new growth that develops has the potential to produce fruit.