Crossville Chronicle, Crossville, TN

April 15, 2013

PLATEAU GARDENING: Spring at last!

By C. Rae Hozer
Chronicle contributor

— The springtime temperatures Plateau gardeners have been waiting for are here. By this time in our state, the sun is high enough and daylight hours are sufficiently long to sustain warmer ground and water temperatures despite a day or two with frosty air temperatures.

After 20 years of gardening in Tennessee’s Upper Cumberland region, I’ve learned that after a string of six days or more in April with highs from 60 to 65 degrees Fahrenheit or higher and overnight lows at or above 40 degrees (such as we have had), installing new plant material is much less risky. However, it is still wise to keep coverings handy to protect cold-sensitive greenery purchases should frosts be predicted.

The hanging pot of trailing pansies (Viola x wittrockiana) I got at a garden center last week is naturally cold hardy. However, the plant tag on a three-plant combo pot (Trixi mix Twinkle Star) I bought to add instant spring color at our sun room entrance calls for protection when temperatures dip below 40 degrees. I like the cheerful contrasting floral colors (bright yellow along with light- and dark-purple flowers) as well as the ease of simply popping the unit out of the purchase pot and into a planter. The mix promises to spread out (up to 24 inches high and 18 inches wide) and give season-long interest. Email about your favorite garden center or nursery plant selections. 

Local University of Tennessee Extension offices and their online publication website are good places to go for free yard and garden information. Staff (and, in some locations, Master Gardener volunteers) there help residents. Bring samples and photos for diagnosis of plant problems/diseases or when you need assistance identifying a weed or insect pest and the best treatment options. They also test soil. (Call 484-6743 to learn the fee per sample). The amount of fertilizer and/or lime required to create the proper environment for the plants to be grown at that site will be included in the soil test report.

April reminders: Lawn treatment options and their timing hinge on whether your turf is a cool-season variety (fescues, Kentucky bluegrass, rye grass) or a warm-season species (Bermudagrass, Zoysia). Fertilizer should be applied when turf is actively growing. Cool-season varieties thrive at 65 to 75 degrees (in early spring and in autumn). Time has run out for cool-season spring lawn fertilization. Warm-season species grow well at temperatures between 80 and 95 degrees Fahrenheit. The feeding schedule for warm-season turf is just starting. Feed that type of grass April 15, June 1, July 15 and on Sept. 1.

Broadleaf lawn weeds are now green and growing. They can be controlled with selective herbicides formulated to kill weeds while leaving grass unharmed. However, weed controls containing active ingredients 2,4,D and Dicamba can hurt very young grass seedlings. Proper watering techniques and cutting grass blades at an appropriate height (not too short) are important for maintaining a healthy lawn.

Need pruning advice? In general, pruning to control tree and shrub size and shape should be done while the plant is dormant in late winter or early spring, before new growth starts. That window of opportunity has passed for many species. Exceptions are trees and shrubs that blossom once each season in springtime. To avoid loss of flowers when these specimens are pruned earlier, homeowners may opt to trim them right after blossoms fade, instead. The booklet “PB1619 Best Management Practices for Pruning Landscape Trees, Shrubs and Ground Covers” is a comprehensive guide available online at

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Plateau Gardening is written by Master Gardeners for gardeners in Tennessee’s Upper Cumberland Region. Contact UT Extension Cumberland County at P.O. Box 483, Crossville, TN 38557 (484-6743) for answers to horticulture questions, free publications and how to become a Master Gardener. Send email comments or yard and garden inquiries to Master Gardener Rae,