Depends what they are Flowerpots. What trees are you wondering about?

And where you are in the country...

If they're roadside or pavement trees in a built up area, councils often have them cut back this time of year; they try to do it just before the leaves fall, less clearing up for the leaf litter crew later. The only reason they do it is because the trees are usually large varieties and get in the way of traffic, phone lines, etc... in other words, it doesn't mean we should all be pruning our trees.

If your winters are fraught with high winds, driving rain & heavy snow load (as mine are), this is a good time to prune off the dead or weak wood, rather then it falling on somebody's head.

thanks everyone for your replies love flowerpots xx