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By: Daniel E. Mullins
Extension Horticulture Agent
Know Light Requirements When Selecting Annuals and Perennials
The amount of sunlight that a planting site receives is the single most important factor to consider when choosing flowering plants. If full sun loving species are established in shade, the results are usually spindly, unhealthy plants that provide little color. In many cases they eventually starve and die due to insufficient sunlight. On the other hand, if shade loving plants are placed in full sun, they often become stunted with small, thickened, burned leaves and produce few flowers.
Matching plants with their light requirement is so important because the amount of light that an area receives is either permanent or is the most difficult condition to change in the landscape. If determined, we can make changes in the soil texture by adding amendments. The fertility level can be changed by adding or withholding nutrients and the soil moisture can be adjusted to some degree by irrigation practices. Changing the amount of light on the other hand, generally requires major and sometimes impractical procedures such as tree planting or removal and the addition or removal of other shading structures.
Last weekend I found myself at a local garden center helping a family member choose flowering annuals and perennials for the spring and summer. We looked at many different species including vines, low growing annuals and perennials. There were two major considerations each time that a desired plant species was found: What is the mature size and does it need full sunlight or shade? Obviously, knowing the mature size of a plant is necessary when choosing one that will remain in scale with the landscape surroundings.
This plant selection adventure reaffirmed my belief that it is much easier to select annuals, perennials and vines for a sunny area than to select for a shady one. With a few exceptions, the most colorful plants generally require lots of light and the list of shade loving or shade tolerant plants is much shorter.
Always ask about each plant’s light requirement before making a purchase. When present, plant tags sometimes also provide this information. Some plants to consider for shady spots in the landscape include Clematis, Confederate Jasmine and Carolina Yellow Jessamine which can be grown as vines. Some ground covers for use under low light conditions are Caladium, Liriope, Partridge Berry, Mondo Grass, Cast Iron Plant, Algerian or English Ivy, Hosta, Big Leaf Periwinkle and Confederate Jasmine.
Areas that receive partial shade, roughly defined as filtered sunlight or sun for half of the day, allow for the successful use of many other flowering plants. These include Begonia, Coleus, Dusty Miller, Impatiens, Pentas, Vinca, Blue Sage, Butterfly Weed, Bush Daisy, Daylily, Shrimp Plant, Mexican Heather, Phlox, Plumbago and Verbena.
Check
gardening references for a more complete list of plants and their light
requirements. The