The rot extends upward into the flower stalks, then the leaves and flowers wilt. Avoid overwatering, use a light porous soil, do not plant too deep, and avoid packing the soil closely around the stem.
Powdery mildew causes a grayish-white, mealy growth on the leaves.
The infected part dries out and the leaves die. This information is for educational purposes only. References to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned. This information becomes public property upon publication and may be printed verbatim with credit to MSU Extension. Reprinting cannot be used to endorse or advertise a commercial product or company.