I have a calla lily plant that I did not plant and it came up right behind my yellow rose bush, and when my roses bloom they look like they are dead and they just bloomed.
Will a Calla Lily Flower Harm a Rose Bush if Next to It?
I would say the two are not compatible and the calla lily should be dug out and moved or pruned out. The rose blooms looking dead could also be caused by thrips or by heat stress. Yellow roses tend to be short lived anyway, so any stresses will just make it worse.