Gardening Life

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Stopping powdery mildew on maples

How do I stop powdery mildew from infecting my maples?

**FULL QUESTION** About three years ago, I planted two maples—a red one and a green one. The red maple developed a white, dusty mold on its leaves and it has now spread to the green one. Do you know what it is and how can I get rid of it? *—Alda Fenninger, LaSalle, ON*

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**FULL ANSWER** This sounds like powdery mildew, a fungus disease that is hitting a lot of maples, especially the red-foliaged ‘Crimson King’ Norway maple. Powdery mildew is more unsightly than dangerous to the tree’s health. However, to help stop further infection, do some judicious pruning (after the trees have fully leafed out) to improve air circulation. Boost your trees’ health by proper watering and mulching with compost. Most important, pick up all fallen leaves. If they are left on the ground, the fungus spores will get into the soil and reinfect the tree next year. *—Marjorie Harris, Editor at Large* Other questions recently answered by the GL team: Finding barren strawberry Lilacs that just won't flower Controlling weeds without chemicals Getting rid of pesky iris borers Finding crabgrass seeds Planting under maple trees Discouraging cats from your garden Hints for growing sweet bell peppers Buying exotic plants in Toronto Preventing brown leaf spot Information on peony-flowered poppies Tips for growing tulips and lilies When to move irises Maintaining blue spruces The best way to grow gunneras Getting rid of sawfly larvae on roses Eliminating earwigs from clematis flowers Beetle damage to spruce trees Removing whiteflies from hibiscus leaves Building a cactus garden Maintaining redbud trees Maintaining Boston ivy growth Using black walnut leaves for mulch

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