Kohleria plants originated in Mexico and South America. They produce tubular and often speckled flowers in a variety of colors, and their foliage can be decorative as well. Although hardy in U.S. Department of Agriculture plant hardiness zones 10 and 11, they are easily damaged by excess water, so they are usually grown as houseplants. Their culture is similar to that of African Violets, but the height of Kohlerias varies from 6 inches (15 cm) up to 4 feet (1.2 m).
Light: Kohleria needs plenty of bright light to bloom. Keep out of direct sunlight.
Water: Spring through fall, water thoroughly and allow the top 2 inches (5 cm) to dry out between waterings. In winter, water just enough to prevent leaves from wilting. Rhizomes store water so it's more tolerant of dry soil than wet.
Humidity: Kohleria prefers relative humidity above 50%, but will tolerate lower levels. Use a room humidifier or a humidity tray to maintain moist air. Don't mist this plant because the hairy leaves will trap moisture, which will cause spots and possibly botrytis.
Temperature: Average room temperatures 65 to 75°F (18 to 24°C). Don't expose your plant to temps below 60°F (16°C).
Soil: Peat moss-based potting mix with perlite added for good drainage. African Violet potting mix is ideal.
Fertilizer: Feed every 2 weeks spring and summer with a high-phosphorus liquid fertilizer (such as 10-30-10) diluted by half.
Put your Kohleria where it'll get plenty of light, but out of direct sun. Filtered light from a south- or west-facing window will give it the light it needs.
Keep the soil evenly moist during the growing season, but take care not to overwater. Dry soil will cause the plant to go dormant. Soggy soil will quickly cause the rhizomes to rot.
You can expect dozens of blooms on plants in spring and summer. You'll get the most blooms by providing plenty of bright, indirect light.
This one likes to be slightly pot-bound, and blooms best this way. Repot in spring when it has outgrown its pot. Always use a container with drainage holes to prevent soggy soil.
Divide rhizomes in spring and pot separately. Or take 4-inch (10 cm) leaf tip cuttings with at least 1 pair of leaves attached and root in moist potting mix. Cover the whole thing with plastic or a glass cloche to hold in moisture. Cuttings root easily in about 4 to 6 weeks.