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  • March garden tips & tasks

    If your fescue lawn looks a little skimpy, overseed early this month. Fescue grows best when the weather is still cool.

    Clip dead stems from perennial herbs – thyme, sage, lavender, rosemary. Pruning encourages vigorous new growth.

    Prune nandinas, flowering quince and other airy shrubs by reaching in and removing about a third of the branches at ground level.

    Remove mulch or leaves that may be covering perennials in garden beds.

    Prepare a new garden bed: Have the soil tested (check with your county’s Extension service). Remove grass and dig or till soil 8 to 10 inches deep and mix with soil amendments and organic matter to improve drainage.

    Add fertilizer lightly to perennials as soon as you see new growth. Too much fertilizer may result in lanky growth.

    Herb transplants that don’t mind cool weather -- parsley, cilantro, sage, oregano – can go in the ground now.

    When you cut daffodils to bring inside, cut the stems at an angle and place them in water right away. Change the water in the vase daily to keep them fresh longer.

    Save the date - Middle Tennessee garden events

    The Perennial Plant Society's annual Plant Sale will be April 8, opening at 9 a.m. at The Fairgrounds Nashville. The sale offers newly released and hard-to-find perennials from top local nurseries -- more than 450 varieties of perennials, vines, grasses, shrubs and annuals. The event supports local scholarships for Tennessee horticulture students and monthly gardening programs, open to the public, at Cheekwood Botanical Gardens. For information visit www.ppsmtn.org.

    The Herb Society of Nashville's annual Herb Sale will be April 29, 9 a.m. - 2 p.m. at The Fairgrounds Nashville. The sale will offer heirloom vegetables, rare varieties of perennial and annual herbs, handmade pottery herb markers and more. To learn more, visit herbsocietynashville.org.

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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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