Botanical Name: Calathea lancifolia
This member of the Marantaceae family is called Rattlesnake Plant for its striking patterns. Long and narrow, the leaves have ruffled edges that are unique to this Calathea species. They are bright green with alternating dark-green markings down each leaf. The underside of the leaves are purple. Of course, they also fold up at night just like prayer plants.
Repot in spring, every year or two to give your plant more room and also to give it fresh potting medium. Use a pot only 2 inches larger than the old one. Why? A pot that's too large will hold too much water and may lead to root rot. When repotting, keep the base of the plant at the same soil level as it was in the old pot. Potting it too deep may cause stem rot.
Keep it clean. Large leaves tend to be dust-catchers. Wipe them off occasionally so they'll get the sunlight they need for photosynthesis. Hold your hand under each leaf to support it, while wiping off dust with a soft, moist towel.
Brown leaf tips may be caused by excess salts in the soil (see "Flush salts" below) or dry air. Humidity can drop drastically in winter without your even noticing it. However, your tropical plants will notice. If your home is as dry as mine, use one of these easy ways to add humidity for your houseplants.
Flush salts. Calatheas are sensitive to fluoride and chlorine from tap water, plus the build up of salts from fertilizer. You've probably noticed white, crusty stuff on top of the soil on some of your potted plants -- either indoors and out -- that's an accumulation of soluble salts. It not only looks unsightly, it can damage your plant. You'll have a much healthier plant if you flush the soil once a year. It's easy, and takes just minutes to do. Here's how: slowly pour room-temperature distilled water over the soil. Allow the water to drain out the drainage holes. Pour more water through the pot, then empty the drainage tray.
Height: 2 ft (60 cm) tall
Light: Bright, indirect sunlight. No direct sun, which will cause brown scorch marks on its leaves.
Water: Aim to keep the potting mix lightly moist; never allow it to dry out. Pot your Calathea lancifolia in a container with drainage holes. Water thoroughly, then empty the drainage tray to prevent soggy soil, which can lead to root rot. Calatheas are sensitive to fluoride and chlorine in tap water -- use distilled or rain water.
Humidity: Marantas love high humidity, and this Brazilian native is no exception. Try to maintain at least 50% relative humidity around your Calathea all year. It's a good idea to use a cool-mist room humidifier near your plant, especially in winter. Dry air may cause brown leaf tips.
Temperature: Warm room temperatures (70-85°F/21-29°C) year-round.
Soil: Peat-rich potting mix with added perlite and/or vermiculite. African violet potting mix is ideal.
Fertilizer: Feed monthly spring through fall with a balanced water-soluble fertilizer. Do not feed in winter.
Propagation: You can divide plant when it gets big. The best time to divide is in spring, when it's starting its most vigorous time of growth.