Hopefully the green thumbs on the board may be about to help me. I'm growing a climbing rose and it is producing flowers, but the flowers are sometimes so big that the stems aren't strong enough to support them. The stems don't just droop over, they sometimes actually bend and the resulting kink will basically kill the flower. Is there some sort of fertilizer that can help make the stems larger and stronger, or is this just a natural habit of some roses? Also, what's best for treating black spot?