Prepared by Karen Russ, HGIC Information Specialist, and Bob Polomski, Extension Consumer Horticulturist, Clemson University (New 06/99. Images added 04/07.)
Coleus are prized for their colorful foliage which may combine shades of green, yellow, pink, red and maroon. New introductions of this popular annual have been selected for increased sun and heat tolerance.
A coleus collection shows a variety of color and leaf shape.
Karen Russ, ©2007 HGIC, Clemson Extension
Coleus vary from smaller types that will reach only 1 foot tall to tall bushy types of 3 feet. Sprawling types suitable for hanging baskets and wall plantings may spread up to 3 feet or more.
Most coleus grow fairly rapidly to their full summer size. They are all tender annuals throughout South Carolina and will be killed by the first frost.
The brilliant and widely varied colors of coleus foliage make it a natural for use in summer bedding and as a color accent. Victorian "carpet bedding" relied heavily on coleus for its bright and intricate patterns. Coleus also grows beautifully in containers, which can be used to highlight patios, porches and garden terraces.
Coleus are highly resistant to serious disease or insect problems when grown outdoors in properly prepared beds or containers. Some pests to watch for include mealy bug, aphids and whitefies. Some disease problems to watch for include stem rot and root rot.
Most coleus will grow best in part shade or dappled light. However, several sun tolerant cultivars are available that will thrive in full, hot sun. They are listed in the cultivar listings below. Varieties that are not sun-tolerant will bleach and discolor in full sun.
Coleus must have good soil drainage. Poorly drained soils and excessive watering will damage coleus. Plants suffering from "wet feet" will be stunted, leaves will turn a muddy brown, and leaf margins will be scorched.
Plants should not be allowed to dry out, however. Water in thoroughly at planting. During the first seven to 10 days, keep root balls moist but not overly wet. Thereafter, water only when top inch of soil is dry (check with your finger every three to five days). Use of soaker hoses is highly recommended.
Coleus grown in containers are more susceptible to drought and should be planted in a very well-drained soil mix that is watered more frequently.
Pinch growing shoots of young plants frequently to encourage and maintain dense foliage. For a mid-summer growth boost, fertilize in June, July and August with a liquid fertilizer at half the usual dilution.
Flower spikes will appear in late summer. Many people dislike their appearance, and if allowed to go to seed the plant will decline. Shear back flowers to extend performance. Vegetative coleus are sterile forms that must be grown from cuttings. They generally flower little in the summer and require less maintenance than seed-grown coleus.
Since coleus are annuals and will be killed by the first fall frost, you may want to take cuttings of especially prized cultivars. They root easily from stem cuttings at any season. Common coleuses can also be grown from seeds.
'Alabama Sunset' is a popular and durable sun-tolerant coleus.
Karen Russ, ©2007 HGIC, Clemson Extension
Coleus That Grow Best in Part Shade
'Fishnet Stockings' is a dramatically patterned coleus for shade.
Millie Davenport, ©2007 HGIC, Clemson Extension
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This information is supplied with the understanding that no discrimination is intended and no endorsement of brand names or registered trademarks by the Clemson University Cooperative Extension Service is implied, nor is any discrimination intended by the exclusion of products or manufacturers not named. All recommendations are for South Carolina conditions and may not apply to other areas. Use pesticides only according to the directions on the label. All recommendations for pesticide use are for South Carolina only and were legal at the time of publication, but the status of registration and use patterns are subject to change by action of state and federal regulatory agencies. Follow all directions, precautions and restrictions that are listed.