Neal - I always bury my bud unions a minimum of 2" and a max of 6" below the surface of the ground, and then pile mulch on top of that. have to do that for my winters. I never uncover the bud union.. I'm too lazy! Now I may move the mulch away from the rose a little when I'm poking around or trimming off winterkill, but other than that, it's 100% buried.
