Members of the Soleonostemon genus are known by their former botanical name Coleus. (Coleus and Solenostemon are the same.)
Solenostemon bears rounded usually toothed leaves on square stems. Leaves are brilliantly colored in swirls and stripes. The blue flowers which appear in whorls are all but an afterthought next to the leaves. Many gardeners pinch away the flowers so as not to distract from the leaves. Leaf colors include green, chartreuse, yellow, buff, salmon, orange, red, purple, brown–and often many of these colors on one leaf.
Use Solenostemon in summer borders and as an indoor or outdoor container pants. Pinch stems to encourage and compact growth.
Solenostemon is a genus of about 60 species of subshrubby perennials. Solenostemon are native to tropical forests in Africa and Asia.
Get to Know Solenostemon
- Plant type: Perennial usually grown as an annual
- Growing zones and range: Zones 9 to 11
- Hardiness: Hardy to Zone 9
- Height and width: Up to 3 feet (.9m) tall and wide
- Foliage: Opposite, rounded, generally toothed leaves on square stems, in various colors.
- Foliage colors: Green, chartreuse, yellow, buff, salmon, orange, red, purple, and brown–often with several colors on each leaf
- Flowers: Tiny, inconspicuous, two-lipped, tubular, blue or white flowers in spikelike clusters.
- Bloom time: Usually grown for the colorful foliage.
- Uses: Bedding, potted plant
- Garden companions: Silvermound (Artemisia schmidtiana)
- Common name: Coleus
- Botanical name: Solenostemon
- Family name: Lamiaceae
- Origin: Tropical forests in Africa and Asia
Where to Plant Solenostemon
- Plant Solenostemon in a sheltered spot with light shade, although it tolerates some sun.
- A site protected from wind is best, and in areas with hot summers the plants benefit from shade during the hottest part of the day.
- Plant Solenostemon in deep, rich, moist, well-drained soil.
- Mass Solenostemon to add color to a lightly shaded border.
- Plant Solenostemon in containers and hanging baskets.
- Placement makes a difference in coloration; too much shade can mute colors; too much sun can bleach color out of leaves.
When to Plant Solenostemon
- Plant Solenostemon seed in early spring.
- Sow Solenostemon indoors 10 to 12 weeks before the last spring frost date at 65° to 70° degrees Fahrenheit (18-71°C). Germination takes 2 to 3 weeks.
- In areas with very long summers—Zone 9-11—seeds can be sown outdoors after the last frost date.
- Set Solenostemon out after frosts are over.
Planting and Spacing Solenostemon
- When sowing Solenostemon, just press the seeds into the soil surface, as light is required for germination.
How to Water and Feed Solenostemon
- Keep Solenostemon moist.
- Water container growing Solenostemon regularly, and feed at least monthly.
- Feed Solenostemon with an all-purpose organic fertilizer in spring.
How to Care for Solenostemon
- Solenostemon is more attractive if kept pinched back.
- Pinch Solenostemon to encourage branching.
- Remove Solenostemon flowers when they appear.
Growing Solenostemon as a Houseplant
- Solenostemon requires bright light; it can also be grown under fluorescent light.
- Solenostemon needs average room temperature and high humidity.
- The soil should be kept evenly moist but not soggy.
- Fertilizer should be applied regularly in spring and summer.
Solenostemon Pests and Diseases
- Solenostemon have few disease problems.
- Solenostemon is susceptible to attack by scale, mealybugs, and slugs.
- Start seeds indoors 10 weeks before the last frost; seeds germinate uncovered in 10 days at 70° to 75°F (21°-24°C)
- Take Solenostemon cuttings of cultivars.
- Take Solenostemon cuttings in late summer for over-wintering, or from over-wintering plants in winter to early spring, to grow plants from the garden.
- Solenostemon cuttings will root in water, sand, or any conventional medium for cuttings, such as a 50-50 mix of peat moss and perlite.
- Since young Solenostemon are the most vigorous—the older ones are more woody—consider growing new ones from cuttings taken annually or every other year.
- Wait to transplant Solenostemon cuttings until temperatures remain above 50° degrees Fahrenheit (10°C).
Solenostemon Varieties to Grow
- Solenostemon scutellarioides, Coleus, Flame nettle, Painted nettle, formerly Coleus blumeii var. verschaffeltii, a bushy, 1-3 feet (.3-.9m) tall tender perennial with leaves that are usually toothed and sometimes heart-shaped at base. Cultivars come with leaves in a mix of colors and patterns, usually with two or more colors as edgings, irregular, or veining. Colors include green, cream, chartreuse, maroon, purple-black, red, orange, and pink. Bears 6 inches (15.2cm) tall spikes of .5 inch (1.3cm) long, pale purple-blue or white flowers, which are usually removed.
- ‘Cinders’ has green leaves with red and yellow spots.
- ‘India Frills’ has small, lobed green leaves with pinkish purple and yellow markings.
- ‘Pineapple Queen’ bears yellow-green leaves with brown-purple markings.
- ‘Purple Emperor’ has ruffled, dark purple leaves with lacy margins.
- ‘Red Trailing Queen’ has deep red-purple leaves with a thin green outline.
- Wizard Series cultivars are compact, 8-10 inches (20.3-25.4cm) tall plants grown from seed.