Cantillon said:Hi Susie,

However I am now beginning to think that the mother tuber rots after one or two years, and may need to be separated. Sometimes when I dig tubers out they split and disintegrate, and it is mostly around the mother tuber.

It may be that the natural development of dahlias is for the center tuber to rot, and the descendent tubers to move out from that location to form their own clumps.

Peter