Fungus on Kalmia latifolia

Asked May 7, 2018, 11:21 AM EDT

Hello. I have 3 Kalmia latifolia elf shrubs planted approx. 7 years ago. They did well the first year but since then have been plagued with some type of fungus. I get lots of new growth in spring but, eventually, all the leaves are afflicted and die. I also notice white powdery stuff on the branches. I spray throughout the growing season with Copper Fungicide but it does not seem to help. I use shredded hardwood mulch around shrubs. Thanks for your help.

Howard County Maryland

1 Response

Kalmias get several fungal leaf spots. Hand pick infected leaves. Clean up all fallen leves and old leaf debris below the plants. It may be easier to simply remove the mulch under them and remulch with clean mulch that doesn't harbor any leaf debris. The object is to reduce the disease inoculum (spores).

Fungicides are preventatives. Next spring, apply a fungicide before you see any leaf infection--or as soon as you see any, pick off the infected leaf and spray. Being pro-active is the best approach.