Calathea- Rattlesnake plant

Calathea- Rattlesnake plant, Zebra plant

By Kim Willis These articles are copyrighted and may not be copied or used without the permission of the author.

Calathea lancifolia

I like houseplants that either have interesting foliage or pretty blooms.  For interesting foliage, the Calathea’s are hard to beat.  There is even one calathea that has attractive flowers as well as good foliage. Calatheas are probably not the best plants for beginning houseplant growers, but those with a little indoor plant experience should be able to grow them.

The calathea species in cultivation are native to Central and South America.  They are tropical and subtropical understory plants with thick, tough leaves.  In their native countries they were often used to wrap small items and make decorative containers by indigenous people. They are sometimes confused with Marantas- the Prayer plant and Herringbone plant.

Calathea leaves have long stems that arise from the plant crown.  In mature plants the leaves can get quite large, up to 30 inches long in some species.  The leaves move to adjust to light conditions, in bright light they are more upright, in lower light more horizontal.  Mature plants, depending on species range from 18 -36 inches high.  The plants increase their width each year with new stems arising from the spreading rhizomatous roots.

Rattlesnake Plant (Calathea lancifolia or Calathea insignis, depending on the reference) is one of my favorite calathea species.  It has long narrow leaves with a wavy edge.  They are pale green on the top, with a purple underside.  What makes it outstanding is the dark green markings on the leaves, which look like an artist carefully painted the stem of another plant on it.  The leaf vein forms the stem in the “picture” with alternating large and small dark green “leaves” along it.  Each of the “leaves” appears to have a tiny stem attaching it to the main “stem”.  The markings mimicking a leafy stem fascinate me, you have to wonder why the markings evolved and I also wonder how the plant got its common name since it does not look like rattlesnake markings to me.  The Rattlesnake plant is also one of the easiest Calatheas to grow as a houseplant since it is resistant to the leaf edge browning many Calatheas have in low humidity conditions.

The Zebra plant (Calathea zebrina) is another common Calathea used as a houseplant.  Its leaves are narrow like C. lancifolia, light green on top with V shaped stripes of darker green and a purple underside.   The Calathea roseopicta has several very colorful cultivars.  This Calathea has broader, oval shaped leaves marked with pink and yellow on top, often there is a yellow outline on the leaf surface, a pink vein and reddish pink stripes.  It has a purple backside too.

Another Calathea, the Peacock plant (Calathea makoyana) has thinner, oval shaped leaves that are white on top with dark green markings. Some think the markings look like the “eyes” on a peacock’s tail but to me they look much like the markings of the Rattlesnake Calathea, with pale green streaking between them.

Calathea crocata is the Calathea that has showy flowers.  This hard to find Calathea has narrow light green leaves striped with darker green and pretty yellow-orange flowers that appear in clusters on top of a long stem that sticks up above the foliage.  Occasionally other species of Calathea pop up on the market

Calathea care

Being from the rainforest Calatheas need high humidity and warmth.  Low humidity is the houseplant growers biggest enemy with this species.  It causes browning and curling of the leaf edges.  Probably the best way to grow them in the home is to sit pots on a bed of moist peat or sphagnum moss.  You could also use a humidity tray under them.

Plants should be in a well-drained potting mix that is kept evenly moist.  They like bright light but should never be placed in direct sunlight, which will cause leaf scorch.  Temperature should be kept above 60 degrees and plants must be kept out of cold drafts.

In the summer months a houseplant fertilizer can be used once a month for healthy, vibrant plants.  Stop fertilizing and water less in winter months.

 All calatheas bloom when mature and in good conditions, but in most species the blooms are insignificant.  Propagation of the plant is by division.  In zone 11 and above Calatheas are sometimes used in the landscape.  They are often used in florist arrangements of decorative potted foliage.

Problems with Calatheas are generally related to environmental conditions.  Browning leaf edges and tips generally mean the plant needs more humidity. Wilting Calathea can mean too much sun, too little water or too much water.  Check the soil and move the plant out of direct sunlight.

When plants are in low humidity they are also prone to spider mites.  Increase the humidity and mist heavily every day for a while to help with this problem. Occasionally Calathea may acquire aphids, mealy bugs or scale, although they are not common problems for this plant.  Treat with a registered houseplant insecticide.  Do not use soap solutions on Calathea as it will cause leaf discoloration.

The ASPCA lists Calathea as non-toxic and I could find no other information on its toxicity.   One species of Calathea, the 6 feet tall Calathea allouia has edible root tubers.  It has not been commonly kept as a houseplant but is cultivated in some areas of South America.