Home & Garden

Fall Planting: Know the Microclimates in your Yard

By early spring last year plant growth was 3 weeks ahead of historical norms for spring leaf and flower break.

Record drought, excessive heat and cold, heavy rains, hurricanes and floods. We have experienced all these extremes over the past several years, and we have reason to expect unpredictability to continue.

The best approach to planting with uncertain weather in our future is still to put the right plant in the right place.

When we select plant for purchase we think in terms of cold temperature tolerance, but that is not the sole indicator whether a plant will thrive in our gardens. Our yards are made up of microclimates which moderate cold temperatures and intensify hot temperatures.

Plant roots grow throughout the winter, albeit slowly, because our coastal soil does not freeze. In the fall and winter newly planted trees and shrubs use their energy to grow their roots. In spring and summer during the growing season plants need their energy for above ground growth of leaves, flowers and fruit.

Some locations in our yards are colder or warmer than others. Sun, compass direction, slope, wind and bodies of water are all major contributors to making a microclimate.

Cold air falls with a slope and lingers at the base. Frost settles and hangs on at the bottom of even a small dip.

Small bodies of water, like retention ponds, affect the temperature only immediately adjacent to them.

Winter winds, especially in open areas, stress plants. Cold wind can damage evergreen foliage and increase a plant’s need for water, especially when a plant is establishing itself.

Houses and adjunct structures, paving, driveways, sidewalks, walls and other hardscapes absorb the sun’s heat during the day and radiate the stored heat at night.

The southeast, south and southwest facing parts of a house receive the most sun and light. The microclimate in gardens facing these directions forms the warmest winter garden. The north side receives mostly shade, making a north facing location the coldest.

Shadows from structures, walls, fences, deciduous and evergreen trees and shrubs all affect how much sun reaches a garden area.

As the seasons change so does the angle the sun and the length of day. When you site perennials and evergreens consider sunlight as it moves through four seasons. Expect that, as they grow, trees and shrubs will add more shade to your garden.

Some plants need higher moisture and humidity to thrive. Site them with easy access to water. Consider proximity to swales, low areas, water elements and other plants. All of these features hold humidity. In addition, low areas retain water longer than higher spots. Beware of slopes where water runs off instead of penetrating the soil.

Air flow is important. Good air movement helps reduce insect and mold problems. On the flipside strong winds stress and dry out plants, especially in high and low temperatures.

Here are some microclimate-wise tips to help you make the most of the various conditions in your yard:

Plant only the toughest sun lovers in open locations with reflected heat from sidewalks, driveways, regularly parked cars, walls and patios.

Site heat tolerant plants in areas such as southern and western exposures where heat builds.

Select an exposure with morning rather than afternoon sun for less tolerant sun loving plants.

You’ll save yourself maintenance by grouping plants according to their water needs. Keep in mind that new plants need to be kept well-watered through their one to two years. Check on them regularly, especially during dry, hot or windy conditions.

Use two to three inches of mulch around a newly installed plant, but hold the mulch away from the base. Mulch moderates soil temperature, conserves water and discourage weeds.

If a plant is to establish a strong root system it will be more successful when planted in advantageous conditions. The right microclimate is a good start.

Reach Debbie Menchek, a Clemson Master Gardener, at dmgha3@aol.com.

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