I bought two Rudbeckia plant late last summer after one of my own 2 plants just schriveled up. I threw out the almost dead plant, moved (for a different reason) the second plant and planted the two new plants nearby.

This year my old plant did the same as the one that died last year. One of the new plants wanted to bloom but the buds seem to be taking a long time to open and the petals seem somewhat stunted. The other new plant is not setting any buds at all. What's going on?