Coleus plants (Coleus scutellarioides) are prized for their colorful foliage, which may combine shades of green, yellow, pink, red, rust, and maroon. New introductions of this popular summer annual plant have been selected for increased sun and heat tolerance.
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 more than 3 feet wide.
The brilliant and widely varied colors of coleus foliage make it a natural for use as a summer bedding plant and as a color accent. Coleus also grows beautifully in containers, brightening shady spots, patios, porches, and garden terraces.
Although coleus do bloom, the inflorescence bears tiny flowers and is not the main attraction of the plant. The insignificant blooms do attract a wide variety of pollinating insects.
Coleus are resistant to most significant disease or insect problems when grown outdoors in properly prepared beds or containers. Some pests to watch for include mealy bugs, aphids, and whiteflies. For information on using insecticidal soaps to control these pests, see HGIC 2771, Insecticidal Soaps for Garden Pest Control. Disease problems in coleus are typically fungal pathogens that cause downy mildew, stem rot, or root rot. Wetting the foliage while watering and excessive soil moisture can lead to these disease problems.
Generally, coleus rapidly grow to their full summer size. All are tender annuals throughout South Carolina, killed by the first frost. Most coleus grow best in part shade or dappled light. However, several sun tolerant cultivars are available that thrive in the full, hot sun. 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” are stunted, with muddy brown leaves, and scorched leaf margins.
Water coleus thoroughly at planting, and do not allow plants to dry out. During the first 7 to 10 days, keep root balls moist but not overly wet. Thereafter, water when the entire top inch of soil is dry (check below the soil surface every three to five days). Use a soaker hose or drip system to deliver water to the base of the plant without wetting the foliage.
Use a very well-drained soil mix when growing coleus in containers. Coleus grown in containers are more susceptible to drought and need to be watered frequently.
Pinch growing shoots of young plants frequently to encourage branching and maintain dense foliage. For a mid-summer growth boost, fertilize in June, July, and August with an all-purpose soluble fertilizer with a formulation like 24-8-16 or 17-4-17. Avoid using a fertilizer formulated for flowering, as the phosphorus content will cause coleus to become leggy and bloom.
Flower spikes appear in late summer. Many people dislike their appearance, and if allowed to go to seed, the plant will decline. Shear or pinch back flowers to extend performance. Vegetative coleus are sterile cultivars that must be grown from cuttings. They generally flower little in the summer and require less maintenance than seed-grown cultivars.
Consider taking cuttings from especially prized cultivars since coleus are tender and will be killed by the first fall frost. While coleus root easily from stem cuttings at any season, some cultivars can also be grown from seeds. Sow seeds uncovered, indoors, on sterile growing medium at 70 to 75 °F. Coleus seeds take 10 to 15 days to germinate and 6 to 8 weeks to reach a size suitable for transplanting outdoors into the landscape or a container. Patented cultivars should not be propagated by cuttings. Plant labels will indicate if there is a plant patent, ‘PP’, or if a patent is applied for, ‘PPAF’.
‘Alabama Sunset’ is an old favorite but still exceptional for its tolerance of full sun. The brick-red leaves have a thin yellow edge.
- ‘Burgundy Sun’ is a coleus from Texas. It has large, oval to heart-shaped leaves that are a deep, rich burgundy. It grows 2 to 2½ feet tall and is slow to flower.
- ‘Burgundy Wedding Train’ is a trailing coleus that has small burgundy leaves edged in lime.
- ‘Chocolate Covered Cherry’ has leaves that progress from pink at the center, and outward to burgundy with an edge of green. It grows well in the sun or shade and reaches up to 14 inches tall. (This is a seed-grown cultivar.)
- Coleosaurus™ (‘UF10-45-12’ PP#27,126) has brightly colored lime-green leaves with dark red markings.
- ‘Dipt in Wine’ has large burgundy leaves with bright gold at the base.
- Inferno (‘UF13-26-7’ PP#28,591) has large, wrinkled, vibrant orange foliage.
- ‘Pat Martin’ is a large plant with burgundy leaves with yellow-green edges. It is a vegetative coleus.
- ‘Pineapple’ is a bright lime-gold with burgundy stems. This easy-to-grow cultivar seldom blooms.
- ‘Saturn’ has bold and distinctive foliage of deep burgundy with a lime-gold center and a thin, scalloped lime edge. Plants grow to 2 feet tall.
- ‘Solar Sunrise’ has deep purple leaves with chartreuse centers that are edged in bright green.
- Redhead (‘UF0646’ PP#21,585) has bright red leaves and is a vigorous grower.
- Wasabi (‘UF0843’ PP#23,585) does well in the sun or shade, and sports deeply-lobed chartreuse leaves.
Coleus That Grow Best in Part Shade
‘Black Magic’ has mahogany purple leaves outlined in avocado scallops.
- ‘Dark Star’ is the darkest of all the black coleus.
- ‘Fishnet Stockings’ has lime-green leaves, heavily veined in dark purple.
- ‘Freckles’ has polka-dotted leaves that are green with red freckles.
- ‘India Frills’ forms compact, carpet-like mounds of tiny, finely cut leaves with elaborate ochre, pink, and purple designs.
- ‘Japanese Giant’ has enormous leaves of pink and violet on a base of burgundy.
- ‘Kong’ series bears large leaves in an assortment of colors. The plants reach up to 20 inches tall and prefer full shade. (This is a seed-grown cultivar.
- ‘Mardi Gras’ has red, green, and yellow leaves and a compact growth habit.
- ‘Red Ruffles’ has red, wavy leaves and green margins.
- ‘The Line’ is tall with elongated gold leaves with a deep purple line along the mid-vein.
- ‘Wizard’ series is a tidy bedding type that reaches only 12 to 14 inches tall. It is available in several individual colors or as a mix. (This is a seed-grown cultivar.)
For further information on preparing a flower garden and planting annuals, see HGIC 1152, Growing Annuals.