Powdery mildew is very common on all varieties of deciduous azaleas. It is virtually impossible to avoid here but some prophylactic spraying with an antifungal can help a lot. Actually, PM is common to rhododendrons period but it just manifests differently on all evergreen species. As with all plants, some species/cultivars are more prone than others. Good air circulation, plenty of sunlight and avoidance of overhead watering should help.

Certain deciduous azaleas mildew heavily here on the West Coast because our dried out soils in summer and moist (dewy) summer nights are perfect for the development of mildew. It would seem that if a particular azalea is mildewing to a bothersome extent even in the eastern North American, rainy summer belt that Michigan falls within then its genetics are ruling against it being practical to keep this variety clean. There's a tendency for thriving foliage mildew on plants to be the result of host susceptibility + dryness at the root + damp foliage at the time of spore germination. This is why it is primarily a summer phenomenon. With it actually being possible to beat it back a bit by hosing plants down (in the morning, so they are not left damp overnight).

Thanks for the info! Sounds like they just may be mildew magnets by nature.

I found Orchid Lights to be mildewy, but haven't experienced that with Northern Hi-lights or any of the other deciduous azaleas I grow, including narcissiflora, a double yellow; Parade, a Weston hybrid; Rosy Lights; rhodora; R. viscosum/swamp azalea; and one whose name I have forgotten with sort of yellow-peach flowers. But I don't know if that is more related to my almost ideal growing conditions for these plants or to their genetics.

I don't recall seeing mildew on neighbors' azaleas when I lived in Cleveland, but I was a less experienced gardener then.

So it might be trying a different type or moving the white lights to a different spot and practicing good sanitation to see how they do. I don't know if your growing conditions are more similar to the PNW or my cold part of New England.

If I can't, out they go - I'm not willing to put up with it. Is this a shrub that is prone to powdery mildew?

==>>> just cant accept them for what they are ... ????

someone who collects variegated plants.. might simply write this off to being an off color plant.. lol ....

otherwise ..... lifes to short ... if they are pissing you off.. off with their heads ...

ken

^^ Nope. Life's too short, at this stage of life anyway, to put up with something that would drive me absolutely batty. Diseased shrubbery in front of the house is not acceptable.