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  • Upcoming Garden Events

    Sept. 30: The Nashville Herb Society presents Through the Garden Gate: A Glimpse of Edwardian England, 8 a.m. – 3 p.m. at Cheekwood Botanic Hall. Celebrate the gardens, foods and flowers that delighted Downton Abby family and friends at the turn of the 20th century. The event begins with a hearty Edwardian breakfast, followed by three speakers: Marta McDowell on Beatrix Potter’s Gardening Life; Geraldine A. Laufer on Tussie Mussie – Victorian art of expressing yourself in the language of flowers; and Terry White, The English Garden event florist . Registration includes breakfast, box lunch in the garden with music, English tea and cookies. To learn more or to register, visit www.herbsocietynashvlle.org.

    Tips & tasks – September

    Cut the dead tops of coneflowers, but leave enough for goldfinches to enjoy the seeds.

    Plant cool-weather vegetables for a fall crop: spinach, mustard and turnip greens, radishes, leaf lettuce.

    Start a new lawn of cool-season grass, such as fescue, or refurbish or repair establish lawns.

    Don’t let the soil of newly planted grass dry out. New grass needs about an inch of water per week.

    It’s still warm, so continue to water and weed garden beds as needed.

    Remove dead foliage, spent flowers and other garden debris; replenish mulch as needed.

    Continue to harvest produce, which may be getting a boost now from slightly cooler weather. Keep watering sage, rosemary and other perennial herbs so they’ll be in good shape to get through winter.

    Prepare to bring houseplants back indoors: remove dead leaves, scrub soil from the sides of the pots, treat for insects. Bring tropical plants in before nighttime temperatures dip to 55 degrees.

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Prevent powdery mildew

QUESTION: How do I keep my beautiful zinnias from getting powdery mildew? It may be too late for this year, but what should I do different next year?

Powdery mildew is a fungus that thrives when nights are moderately cool and foliage stays damp. It travels by airborne spores, and appears as gray or white splotches on leaves, stems and flowers of susceptible plants, such as zinnias. A mild case is merely unattractive; a severe case of powdery mildew can cause distorted shoots and leaves, misshapen flowers or can prevent flowering altogether.

The best defense is to give zinnias room to grow without crowding, which allows air to circulate better around the plants, and water only in the morning, so the foliage has time to dry before nightfall. Cut back on the use of high-nitrogen fertilizer, which produces succulent new growth that is a major powdery mildew magnet. Grow them in full sun; hot temperatures (above 90 degrees) inhibit the growth of mildew.

There are fungicides available that should be applied as soon as you begin to spot the mildew (so yes, probably too late for this year), but I always suggest trying the good-cultural-practices method first. The University of Tennessee Extension has a short list in a publication about powdery mildew here. If you decide to go that route, be sure to read and follow directions on the product label.

Zinnias are not the only things plagued by powdery mildew. Lilacs, roses, crepe myrtles and other woody ornamentals, and many herbaceous ornamentals and bedding plants are also targets when weather conditions favor the fungus.

 

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