My rhubarb grows in the most horrible clay soil, and all I ever do is throw a bit of wood ash on it in spring when I go round the fruit bushes.
It's looking good at the moment.
We had a quite a hard frost last night (in Lincolnshire) - the chicken's water was frozen over and the pond - complete with lots of frog spawn, had a layer of ice. It's cold again tonight - don't hold out much hope for the frog spawn!