A microclimate could be the reason a plant refuses to thrive, the explanation for a spot where nothing grows or why certain plants in your neighbor’s yard look better than yours.
Get to know the warm season microclimates that exist in your yard. Microclimates are more than climate defying warm spots that get marginal plants through the winter.
Cold tolerance as indicated by our climate zone is not the sole indicator of whether a plant will survive in a garden. Yards are made up of microclimates which modify cold temperatures and intensify hot temperatures, spots where aspects of the local climate are intensified or moderated.
A microclimate is a small area that has a different climate from the surrounding larger area. These spots can be as small as several square feet. Such anomalies can be wonderful for certain plants or they can be a challenge.
What causes microclimates? Structures, sun exposure, temperature, moisture, terrain and wind can alter the climate in small areas.
Shadows from structures, walls, fences, deciduous trees and evergreens affect how much sun reaches yard and garden areas. As the seasons change so does the angle of the sun and the length of day. Consider the amount of sun a plant receives through the four seasons.
For example, when you plant in spring, the sun is already high in the sky and a particular garden spot may receive full sun. However, in winter when the sun is lower in the sky a building may block much of the sun to that area, leaving it in part shade half the year.
Buildings not only cast shadows, but reflect and hold heat and deflect wind. They have significant impact on the conditions surrounding them.
Roof overhang blocks rainfall and reduces the moisture level in the soil below. The eaves on the north side of a house can produce deep dry shade.
Heat sinks (gravel, paving, rocks, decks) retain, reflect and release heat. That increases the temperature in adjacent sunny areas.
Humidity level changes from spot to spot. Swales and low areas hold moisture longer than higher areas. Water features elevate humidity in their immediate vicinity. A group of plants together increases the humidity level where they stand.
Strong winds stress and dry out plants especially at high and low temperatures. Hedges, solid fences and walls protect against wind, but they can also form wind tunnels or cause winds to swirl.
Microclimate-wise Tips for Planting the Right Plant in the Right Place
An east facing exposure provides morning sun and afternoon shade. It is ideal for plants that take full sun/part shade. Shade lovers can sometimes handle this condition because morning sun is less intense than it is in the afternoon. Morning sun often works for sun loving but less heat tolerant plants.
A south facing location supports the longest growing season. This exposure is good for a subtropicals, citrus and vegetables gardens.
A west oriented garden is hotter, windier and drier than other exposures. It is a good choice for plants that thrive in a Mediterranean climate.
A northern exposure receives the least sun. The ground retains moisture longer. If you want grass plant a shade tolerant variety.
Site heat tolerant plants in southern and western facing locations where heat builds during the day.
Plant only the toughest heat and sun loving plants in open areas with reflected heat from driveways, sidewalks, paving, regularly parked cars, walls and patios.
Be aware of slopes where water runs off instead of penetrating the soil. Use drought tolerant plant material to withstand the dryness and help limit erosion.
Choose plants with thick, leathery or waxy leaves for windy areas.
Early spring bulbs can do well under a deciduous tree. They get the sun they need to bloom, and by the time the tree leafs out the bulbs no longer need sun.
Relocate plants that fail to thrive. Transplant them from a stressful area to one that is more supportive.
You will know when you have the right plant in the right place because it will thrive.
Reach Debbie Menchek, a Clemson Master Gardener, at email@example.com.