Chrysanthemums, or garden mums, typically die due to disease or pests if they are being properly cared for. Although mums are one of the hardiest of plants, a number of diseases can kill them.
Leaf spot is a common disease found on mums and is caused by fungi such as septoria chrysanthemi, Septoria chrysanthemella and Alternaria. Yellow spots appear on the bottom leaves first and gradually darken until the leaves drop. Other common diseases include:
- Foliar nematodes: tiny unsegmented roundworms that enter leaves through the stomata
- Wilt: another fungal disease that can gradually cause stunted growth and death of the mum
- Bacterial blight: a disease caused by Erwinia chrysanthemi that causes the collapse of the distal portion of the plant.
Planting chrysanthemums in direct sunlight and regularly watering while inspecting for signs of potential disease or infestation will ensure the health of the plant.