Coleus plants are one of the rare plants that are grown almost exclusively for colorful foliage. Surprisingly, they are members of the huge mint family; like peppermint, their leaves are sometimes used for medicinal purposes (though they are not particularly tasty).
Coleus is a hardy, attractive plant that is available in a wide range of sizes and colors. Some varieties grow as bushes, making them inappropriate for indoor locations. Many, however, thrive in pots under the right conditions.
Coleus plants are truly in their glory in masses—their leaves are available in green, purple, orange, red, yellow, and in a striking array of patterns. Coleus is also fun propagate; new plants grown from seed will be new creations. Although the directions below make it possible to keep coleus indoors year-round, coleus is often grown as an annual and discarded once it becomes leggy (a problem that can often be contained by pinching off new growth).
Indoor coleus does best under the following conditions:
- Light: Coleus loves bright light, though its best to avoid direct midday sunlight. Too much sun will wash out the colors in their leaves.
- Water: Keep soil continuously moist throughout the year, but reduce watering in winter. High humidity is preferred.
- Temperature: Above 60 F is preferred in the summer. In winter, above 50 F is best.
- Fertilizer: Feed in spring with slow-release pellets or weekly during the growing season with liquid fertilizer.
You can propagate coleus by cuttings or seed. Cuttings will be identical to the parent plant, but newly seeded plants will be variable. Plants that are grown for propagation, however, generally do not look as good as ones grown exclusively for their foliage. The energy of flowering usually saps the plant of some vitality, which is why many growers pinch off flowers.
A large coleus will reach only 2 to 3 feet. They grow rapidly in the spring, but many people don't overwinter them, so they never bother repotting the plant. If you choose to grow coleus for more than one season, you might consider trimming the plant back after the winter, refreshing the soil, and keeping it in the same pot. Alternatively, go up one pot size.
There are about 60 species of coleus, all native to Asia and Malaysia. However, virtually all of the coleus available are derived from the single C. Blumei species, crossed with a few other species. Hybridizing work within this group has been extensive—there are literally hundreds, if not thousands, of cultivars. Buy coleus for its leaves and don't worry too much about its parentage.
Growing coleus indoors is definitely possible, providing you give it enough moisture, heat, and humidity. If the plant goes into flower, snip off the unremarkable flowers to encourage vitality, and pinch off growing tips to encourage bushiness. Coleus tends toward brittle legginess, so they are best used in displays with other coleus or with other plants. If the plant starts to lose its leaves, it's probably too dark or cold. If the color washes out, it's probably getting too much sun.