I have a trachycarpus in my back garden. It is now about 15 feet high. Can i stop it getting any bigger? I really don't want to have it chopped down as it is so beautiful.

It won't get much bigger, in terms of crown size, it will mainly get taller. But it does get harder to pump the water up as it gets taller, so it will slow down. Limit watering and avoid fertilising.