It seems like every plant that I come across has a different (and seemingly random) best time to prune. Is there some sort of generally rule that I could apply to any plant and have a pretty good idea when to prune.
I really don't want to have to identify and google every time I come across a new plant. Also, what are the consequences of pruning a plant at the wrong time?
It really comes down to the type of tree eg Fruit, Deciduous, Evergreen, etc then the specific species as to when is (considered) the best time of year to prune...
The same is true for plants.
As a very general rule of thumb, prune in:
Dead of Winter.
Or Spring (exact time during Spring will depend on what it is you're pruning) through to early Summer.
Best to avoid mid to late Summer pruning, though there are exceptions to that case...
Never prune in the Autumn (Fall) or early Winter.
Rule of thumb: prune heavily in winter/spring before growth starts. If you prune lightly in late summer/autumn, only remove green (not wooden) parts.
So much for rule of thumb. There's a lot of variation depending on the actual plants, location, potting, and climate. I prune my indoor chilis whenever they get too big and I can do so without cutting off the harvest, and they seem to do well.
It is one of those confusing things for a beginner - and you don't want to kill the plant. However, in most cases I don't think it is too critical. You might want to time pruning to induce flowers (eg. roses), or to avoid the chances of disease (eg. trees heal better at particular times of the year) - those would require particular timings but aren't critical to-the-week.
Also if you want to use the prunings for something. I've pruned our young peach three times now - it doesn't seem to care when I do it, but cuttings from the prunings do much better if they are cut in spring just before the leaf buds come out.
