Ask Burton: This week, the fungus is among us! Q: My flowerbeds and a row of my shrubs need some help. My coreopsis look terrible, with some of the leaves turning grey, and I have mildew and some sort of spotting on the lower leaves of my crapemyrtles. I also have a row of redtip photinias along my back fence, and they’re covered in angry red spots. My periwinkles are dying day by day – it started with a couple of individual plants, and every day, more turn brown and die.

A: The rain is largely to blame for this. Cool, moist weather encourages fungal growth on your flowers and shrubs, and we’ve had so very much of it lately.

The coreopsis have powdery mildew. The crapemyrtles have powdery mildew and cercospora, and the photinias have entomosporium leaf spot. The periwinkles are dying of phytophthora. Now that we’re done with the fancy names, here’s how to go about dealing with the problems.

Coreopsis (and other small perennials with mildew): Trim the plants back and throw the clippings away. Spray with one of several effective fungicides. Generally, we recommend our ferti-lome Systemic Fungicide for most fungal disease issues on ornamentals and common flowers. The new growth will come out undamaged. These are probably fixable.

Crapemyrtles: Sunnier, drier weather would probably clear most of your problem up; but apply the fungicide twice (ten days or so apart) to knock the problem down faster. Rake away leaves as they fall to help prevent re-infection later. Your crapemyrtle is in no danger of dying.

Photinias: This one is harder, honestly. You can suppress the problem this time and get the plant to put on clean new growth with repeated applications of ferti-lome Systemic Fungicide. Rake away diseased leaves as they fall to prevent reinfection later and apply sulfur to the soil beneath the plants. Entomosporium leaf spot is stubbornly persistent on susceptible plants. Once a plant has had a bad bout of the disease, you’ll need to watch it closely – it’s likely to show up again each spring and fall.

Vinca (periwinkles): This problem cannot be solved by spraying. Pull diseased plants and throw them away. Mulch beds with vinca in them to reduce soil splash, which spreads the soil-borne disease easily in rainy weather. Keep beds of vinca on the dry side, and if you have a flowerbed become infected, replant with a different flower. Angelonia, penta, and celosia are all good substitutes in sunny, hot beds. The problem rarely fades with time; if you like vinca but your beds have been infected, plant them in above-ground containers with fresh soil.