Rattlesnake Calatheas (Goeppertia insignis, formerly Calathea lancifolia) are fascinating, attention-grabbing plants from the Brazilian tropics that are perfectly safe for your family and pets. However, they are known for being tricky houseplants and are a good choice for experienced indoor gardeners.
Rattlesnake Calatheas’ lance-shaped leaves ripple slightly with green-on-green ovals, giving them a reptilian look. When the sun goes down, the plants turn their leaves upward, revealing the rich burgundy undersides, and then they bend them back down in the morning light.
Members of the Prayer Plant family (Marantaceae) use this leaf movement (nyctinasty) to capture the maximum available sunlight. They do this by changing the water pressure in the nodes below the leaves and in their stems.
Providing the right combination of temperature, light, and moisture in my household environment has been trial and error so that my plant is healthy and bends its leaves up and down with the cycle of sunlight.
Here are tips for the care I found that works well for Rattlesnake Calathea.
Care Tips for Rattlesnake Calathea
Pay close attention to their care needs and adjust them according to your indoor environment, and you will be rewarded with a striking display.
Light
Calatheas (Goeppertias) thrive in bright, indirect light. They are understory plants that get filtered sunlight from above through the trees in their native environment.
Avoid putting your plant in a window with direct afternoon sun, or its delicate leaves will burn. A bright east- or north-facing window will give it good light, or even in the interior of a brightly lit room.
Temperature and Humidity
Calatheas need warm temperatures and plenty of humidity to thrive. Their best temperature is between 65 and 75 degrees F. But be careful of drafts. They will not do well in hot or cold air currents from heaters, air conditioner vents, or cold, drafty windows.
As rainforest plants, Rattlesnake Calatheas require 50% or higher humidity, which is more humid than most households, especially in the winter when the heat is on.
If there is enough light, you can set your plant in a higher humidity area of the house, like the kitchen, bathroom, or laundry room. I keep mine on my kitchen windowsill above the sink, and it’s happy there with the humidity and warmth.
You can create more humidity around your plant by using a pebble tray with water and carefully keeping the bottom of the pot above the water line. A daily misting is helpful, and a humidifier is excellent, too, if you have one.
Soil
Soil for your Rattlesnake Calathea must be light, well-draining, and slightly acidic. You can buy a commercial potting mix and amend it with peat moss, coco coir, or perlite.
You can also make your own, which is more cost-effective. Peat moss with perlite in a 3:1 ratio is light, well-draining, and acidic, perfect for Rattlesnake Calathea.
Pots
Plant pots come in an enticing array of colors, shapes, sizes, and materials. When you choose a pot, make sure it has at least one drainage hole in the bottom so it can drain quickly and keep the roots from sitting in water.
The size of the pot is important, as well. Too small a pot will cramp the roots and prevent the plant from growing and expanding. A pot that is too big will hold a lot of soil, which will hold more water than the plant can use, putting it at risk for root rot.
The “just right” pot size is one inch bigger around than the plant.
Water
Watering your Calathea the right way is essential for its well-being. The formula I use to keep my Rattlesnake happy is to allow water to run through the soil and out the drainage holes once every two weeks during the spring and summer.
Then, during the days between, I water a small amount when the top of the soil is dry. This ensures that the soil is moist but never soggy. I cut back on the water during the fall and winter months when the plant is not actively growing.
Calathea leaves will curl if the soil is too dry, and their leaves will turn yellow and drop with too much water. So, pay attention to the leaves and the soil to gauge when to water your plant.
Fertilizer
To supplement the nutrition from the soil, fertilize your plant with a balanced liquid fertilizer about once a month during the spring and summer. If you prefer a slow-release granular fertilizer, sprinkle a little into the soil twice during the growing season.
It won’t need fertilizer during the fall and winter when its growth has slowed.
NOTE: It’s best to dilute the fertilizer to half-strength to guard against fertilizer burn that will prevent the roots from absorbing water.
Pruning
Since Rattlesnake Calathea grows one leaf atop each stem and doesn’t become long and leggy, it only needs a little pruning to clip out dead or damaged leaves.
Pests
The pests that can commonly feed on your plant are aphids, spider mites, and mealybugs.
Aphids are small, green, or black, pear-shaped insects that suck plant juices and cause the leaves to curl and turn brown. They also secrete a sweet liquid called honeydew that can promote mold growth.
Spider mites are small, eight-legged creatures that also suck plant juices and cause curling and stippling of the leaves. Even though the bugs are tiny, they spin easy-to-see webbing over the plant.
Control aphids and spider mites with a spray or wipe-down of insecticidal soap or Neem oil on all surfaces of the leaves and stems.
Mealybugs are fluffy, cottony insects that attach themselves to leaves and stems and suck plant juices, causing distorted, wilted foliage. Luckily, they are easy to see and remove.
You can control these bugs by picking them off with tweezers and spraying the plant with horticultural soap, Neem oil, or a 3:1 solution of water and 92% isopropyl alcohol with two tablespoons of Dawn dish detergent stirred in. If you have a heavy infestation, you may have to repeat the treatment until the pests are gone.
Propagation
Since Rattlesnake Calatheas grow up from the soil with one leaf per stem, the best way to propagate them is by division. Here are the steps to easily divide your plant:
- Water your Calathea a day before you plan to divide it so that it will be easier to handle.
- Tip the pot on its side and gently pull out the root ball.
- Shake off enough soil so that you can see the roots.
- Split the root ball into two or three parts by cutting it with a clean knife or gently pulling it apart with your hands, careful not to damage the roots.
- Set them in a warm, bright spot and keep the soil lightly moist.
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Nancy has been a plant person from an early age. That interest blossomed into a bachelor’s in biology from Elmira College and a master’s degree in horticulture and communications from the University of Kentucky. Nancy worked in plant taxonomy at the University of Florida and the L. H. Bailey Hortorium at Cornell University, and wrote and edited gardening books at Rodale Press in Emmaus, PA. Her interests are plant identification, gardening, hiking, and reading.