Crossville Chronicle, Crossville, TN

October 7, 2013

Plateau Gardening: Landscape planning

By C. Rae Hozer
Chronicle contributor

CROSSVILLE — Landscape plants enhance a home’s unadorned good looks, adding curb-appeal. That increases your property’s value. Plantings make other practical contributions, as well. Think beyond aesthetics when selecting the best plant for a particular function or when determining whether a certain plant should be removed from your landscape.

My neighbor consulted an arborist after the fellow delivering propane pointed out the trunk of a nearby tree had grown enough to press against the tank for the gas needed to fuel their heat and air conditioning system. The deliveryman said the tree should be removed. When the tree expert came out to take a look, his opinion was the tree should stay. He explained his reasoning. The large tree was healthy. Removing it would cost the homeowner money in more ways than just the fee for cutting the tree down and hauling the wood away. The tall hickory’s canopy of leaves blocked the western sun each afternoon. The tree shading their roof kept temperatures in their house cooler during summertime. If the tree was cut down, they would need to rely on air conditioning during hot weather to achieve the same cooling effect. Their energy costs would be higher every year the summer sun was allowed to beat down on their roof unimpeded. A one-time charge to relocate the tank five or six inches away from the tree trunk would be inexpensive in comparison.

Be aware of the beneficial cooling large deciduous trees located to the west and/or south of your home can provide. Energy studies indicate the combined effect of a landscape with a healthy lawn, shrubs and trees can reduce temperatures between 7 and 14 degrees. Evergreens keep their foliage year round but trees that shed their leaves cool with shade when it is hot then while their branches are bare in autumn, winter and early spring allow solar heating from sunlight to warm your house.

Plants and turf further enhance our environment through the process of photosynthesis by pulling carbon dioxide from the air and in exchange put oxygen and water vapor out into the atmosphere. However, those with inhalant allergies would be wise to consider the amount of light-weight pollen landscape plants like certain needle evergreen varieties and most nut trees spew into the air in springtime. On the topic of air quality; golden rod has traditionally been blamed as an autumn allergen source by hay fever sufferers. Plant scientists say that is untrue. The real culprit is ragweed. It blooms at the same time we see golden rod’s yellow flowers. Golden rod pollen is heavy and not easily air borne. However, pollen from ragweed’s little green flowers is light enough to be easily moved by slight breezes. Increased carbon dioxide levels in the atmosphere have caused noxious weeds like ragweed to flourish and grow bigger than ever before.            

Size needs to be appropriate to a plant’s purpose in the landscape. Foundation plantings and trees in the yard should not be so big they tower over the house or hide it from view. Measure the distance from the soil surface to window sills. Research to find cultivars of a shrub you like for its good looks that will grow just up to or a bit below the bottom of your windows. Purchasing shrubs whose potential height is much taller dooms you to pruning every year after the plants mature. Too-tall foundation shrubs not only block views from within to  the outside, they also shut out incoming natural light making a home’s interior seem overly dark and giving occupants a feeling of being closed in. Plants used in hedges or as screens should be tall enough and sufficiently dense to hide unappealing sights or block noise.

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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, MGardenerRae@frontiernet.net.