One of my Ladies, has a massive stand of Pampas Grass. I have been told it needs to be burnt down every 3 years. I cut out all the dead stuff last Autumn (Fall) This plant had not been attended to for years, was at least 25 feet tall, sorry, don't do metric! Fantastic plant and want to do what is right by it. I live in the very temperate South Coast of England. Advice on how to, and when would be gratefully received.