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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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Lovely roses, ugly leaves

QUESTION: I have two rose bushes and the flowers are beautiful, but there are small, irregular holes in some of the older leaves. My neighbor’s roses have black spots on the leaves. What causes these things?

rose redThere seem to be so many things that can bug roses: aphids, spider mites, Japanese beetles, thrips. Blackspot, anthracnose, mildew.

Damage to leaves is most often caused by insects. If you find holes in the leaves of your rose bushes, most likely they have been visited by the chewing kind. One likely suspect may be the little caterpillars known as rose slugs, the larva of an insect called a sawfly.

A little research reveals that the adult lays her eggs on the leaf surface, and when the larvae hatch they move to the underside of the leaf and begin feeding, creating holes between the veins. Finally, the larva drops to the ground, and later emerges as an adult sawfly, ready to begin the cycle again. There can be six generations a year.

Rose holesThe best method for eradication is to pluck these things off the leaves when you see them. Examine the undersides of the leaves, particularly, for the ¾-inch, lime green caterpillars. If you feel you must spray something, a pyrethrin product is advised.

The black spots on rose leaves could be one of several possibilities: Anthracnose is a fungal disease that causes black spots that later turn purple or brown. It thrives where conditions are moist. Downy mildew begins with irregular purplish spots that turn black. The most common, though, is a condition called blackspot, another fungus that thrives in moist conditions.

These diseases overwinter on old leaves that fall to the ground, so it’s good gardening practice to clean up around the base of the shrubs and remove dead foliage. The experts at the Nashville Rose Society recommend a regular fungicide spray schedule beginning in the spring.

With all that can go wrong with roses, why bother growing them? Because if you have the right sun and soil conditions, they can be one of the most rewarding plants in the garden.

Eating extra-local — from your back yard

Find ideas for all that zucchini, that basket full of okra, all those tomates, plus summer garden tips and tasks in the August Garden Calendar at Tennessean.com.

Garden events in Middle Tennessee

August 20: Julie Berbiglia of NPT’s Volunteer Gardener is the speaker at this month’s Perennial Plant Society of Middle Tennessee meeting at Cheekwood’s Botanic Hall. Her topic: “Water Conservation.” Refreshments at 6:30, meeting at 7 p.m. The public is invited. www.ppsmt.org.

August 22: Hosta hybridizer Bob Solburg of Green Hill Farm in Franklinton, N.C. is the speaker at this month’s meeting of the Middle Tennessee Hosta Society at Cheekwood. The meet-and-greet begins at 6:30, meeting at 7 p.m., and Solburg will have plants for sale. www.mths-hosta.com.

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