Coleus (Solenostemon scutellarioides)

Impatiens is on the “no grow” list for 2013 because of fears that the mildew that wiped them out last year will persist. Gardeners with semi-shady areas will be looking for a plant that grows under similar condition. Coleus (Solenostemon scutellarioides), also known a flame nettle or painted nettle, makes a great substitute for the long favored impatiens.  Coleus is grown for the leaf color so it has the advantage of being an attractive plant all summer.

There are 60 species of coleus found throughout the tropical regions. Most of the ones found on the market today are bred from Coleus blumei now known as Solenostemon scutellarioides. There are hundreds of different varieties ranging from almost black, through shades, of yellow red orange and green to the palest of pinks. Sizes range from 6-8 inches to 2-3 feet. Some are very fast growers and some will remain the same size throughout the season.

Coleus will grow in dappled shade or partial shade. Morning sun is tolerated but generally full afternoon sun is not  There are varieties of coleus that are more tolerant to sun than others but they are generally not a sun loving plant. The more tolerant varieties can be gradually introduced into brighter light. The


Coleus in Border

colors will be less intense in sun and the leaves may bleach out if the light in too intense. Shade intensifies the colors but if the plant isn’t getting enough light it may become leggy. Disease is also more likely to develop in deep shade conditions where the soil is likely to be damp.

Coleus is an annual and is often planted outdoors in pots. Although some coleus grow bigger and faster than others, a 6-8 inch pot will usually house a single coleus plant for the growing season.  A 10 inch or larger pot is needed for 3 to 4 coleus plants. Whether in a pot or in the ground, coleus needs rich well drained soil. A good water supply is necessary. Coleus wilts easily and, while it will come back with the addition of water, repeated wilting will weaken the plant. In a pot twice daily watering may be necessary in dry weather.

Because coleus is grown for its leaf color it is important to keep the leaves in good condition. It is best to water in the morning and at ground level. Water on the leaves can cause spotting, browning and fading of the color. Plants in the ground should be mulched to keep the ground from drying out. It is important to keep the mulch away from the stems of the plant to prevent rot and discourage snails. Never mulch coleus with cedar mulch, as it is fatal to this plant. Fertilize sparingly to encourage the best leaf color.

When planting coleus in the ground it is better to plant larger plants with extensive root systems. If smaller plants are purchased it is advisable to put them in 4 inch pots and grow them larger. When they have a good root system they should be gradually hardened off. If they are being grown indoors place them in an n outdoor location sheltered from sun and wind for a few hours each day, gradually increasing the time. Move them into more light as they become accustomed to the outdoors. Coleus are a tropical plant and do not do well in temperatures below 60 degrees. They will tolerate temperatures into the 40’s or 50’s but these cooler temperatures will inhibit growth and encourage disease. Coleus loves hot weather but a frost is deadly.

Coleuses that are healthy and grown in well ventilated conditions, with sufficient sunlight and appropriate water supplies are relatively disease and insect free. Removing any damaged leaves will keep molds and mildews under control. Insect pests include aphids, mealy bugs, whitefly and spider mites. All are more common on indoor plants than on those grown outdoors. Slugs can be controlled with common slug baits.

Coleus should be regularly pinched back and shaped. The faster growing varieties will need more grooming than the slower growing ones. The flowers are not spectacular and should be removed. Allowing the plant to bloom and set seed will use energy which is more productively channeled into the growth of new leaves.

One of the nice things about coleus is that they are very easily rooted. A cutting from a non- flowering stem will root in a week or so in water and quickly provide another plant. This is a good way of over wintering the really attractive color combinations. Since some of the newer colors are quite expensive this is a useful trait.

Give coleus a try this summer. Perhaps impatiens will be replaced in your gardening lexicon.