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Publication #ENH1030

Cultural Guidelines for Commercial Production of Interiorscape Calathea1

Jianjun Chen and Dennis B. McConnell2

Calathea is a member of the family Marantaceae and native to tropical regions of the Americas. The total number of species in the Calathea genus has dramatically increased during the past 50 years, and taxonomists now list about 300 species. Calatheas are perennial rhizomatous or tuberous herbs and have undivided long elliptic to ovate leaves. Some species have only basal leaves while other species have their leaves on short stems. The leaves may be smooth and shiny or covered with small fine hairs, depending on the species. Inflorescences of most species are borne terminally but hidden in their long petioled leaves. Only a few species, such as C. crocata and C. loeseneri, have inflorescences that project above the foliage canopy.

Among the cultivated species, C. allouia is produced for its small gritty tubers, which are eaten like potatoes in the West Indies and northern South America. Some large-leaved species, such as C. lutea, are potential sources of commercial wax, resembling carnauba wax, which is obtained from the undersurface of leaves. Most other Calathea species are grown for their stunning attractive foliage. Their brilliant patterns of leaf color, texture, and elegance attracted wide attention as early as 1861. However, production of calatheas as ornamentals was limited to just a few species until recently new species introduction. In 1975, only three species (C. insignis, C. makoyana, and C. roseopicta) were commonly grown in the US; but now at least 15 species and about 35 cultivars are commonly produced. New cultivars continue to be released by tissue culture laboratories, primarily from somaclonal variants.

This article is intended to describe common cultivars grown in the foliage plant industry, provide guidelines for their culture and interior use, and list physiological problems that may be encountered during production and interiorscape use.

Cultivars

See Table 1.

Cultural Guides

1. Propagation

Calathea species can be propagated by division. The rhizome is divided so each piece has at least one leaf, and then is planted in appropriately sized pots. Only a few species, such as C. micans, can be propagated by seed. Currently, almost all commercial production uses liners from tissue culture.

2. Production

Liners are transplanted in either 6- or 8-inch pots and grown in shadehouses or shaded greenhouses. Soilless media formulated with peat, pine bark, vermiculate, and/or perlite with a pH around 6.0 and soluble salts of 1 to 2 dS/m are suitable for Calathea production. Plants should be grown under at least 80% shade (1000 to 2000 foot candles), with relative humidities between 50 to 100% and temperatures between 70°F and 90°F.

If plants are fertigated via drip or ebb-and-flow irrigation, a nutrient solution with N at 150 ppm can be used. This solution can be made using a water-soluble fertilizer with N-P2O5-K2O at a 3-1-2 ratio, such as a 24-8-16 or 18-6-12 with micronutrients. If a controlled-release fertilizer with the N-P2O5-K2O ratio of 3-1-2 is used, apply it at rate of 3 lb N per 1,000 square feet on a monthly basis.

Potting media should be kept moist but not over-watered when controlled-release fertilizers are used. Growers are strongly recommended to monitor pH and the nutrient status of potting media by checking soluble salts levels at least monthly using pH and electrical conductivity (EC) meters. Media solution can easily be extracted by the pour-through method. If EC readings fall below 1.0 dS/m, additional fertilization is needed, whereas if EC readings are above 3.0 dS/m, growers should reduce either the frequency or amount of applied fertilizer.

It is recommended that fertilizer applications be reduced or eliminated one month before plants are shipped. Leaf nutrient concentrations listed in Table 2 provide a general guide for determining if Calathea is appropriately fertilized.

Shipping and Interior Care

Shipping sleeves are needed for transporting finished Calathea. Recommended temperature range for shipping is 60°F to 65°F as exposure to a temperature below 55°F may cause chilling injury. Irrigate the media thoroughly the day before shipping to reduce stress during transportation.

Calatheas tolerate an interior light level as low as 75 foot candles; but optimal light levels range from 150 to 200 foot candles. Plants maintain their aesthetic appearance better if relative humidity is kept between 40% and 60%. Allow the surface of potting media to dry slightly before watering. Temperatures should be kept between 65°F and 80°F indoors.

Figure 1. 

Commercial production of Calathea cultivars in a shaded greenhouse.


Credit:

Jianjun Chen, UF/IFAS


[Click thumbnail to enlarge.]

Physiological Problems

See Table 3.

Tables

Table 1. 

A listing of common cultivars of Calathea in Florida as of 2005.

Species

Cultivar

Characteristics

C. fasciata

Fasciata

Large round leaves, green with wide dark stripes on the upper leaf surface and a purple lower leaf surface.

C. insgnis

Insgnis

Oblong leaves with wavy margins; yellow-green upper leaf surface having alternating large and small dark green spots; a purple lower leaf surface.

C. kennedeae

Helen

Thick leaf with dark green margin, and "paint brush strokes" of the same color on a silver interior.

C. loeseneri

Kopper Krome

A sport of C. loeseneri with dark coloration under the leaf, giving the plant a darker, hardier look. The showy part of the inflorescence is a much darker pink than the species.

 

Loeseneri

Green leaves with a lighter green mid rib. The lavender inflorescence is borne above the foliage.

C. majestica

Majestica

Light green leaves and pinkish-white stripes covering the upper leaf, purple lower leaf surface.

C. makoyana

Makoyana

Oval leaves that are cream or pale green with dark green oblong blotches along lateral veins.

C. orbifolia

Orbifolia

Bold, striped, luxurious foliage

C. ornata

Ornata

Oblong shaped dark green leaves with pink stripes going from the mid rib to the margin. The deep magenta underside makes this one of the most popular Calathea.

C. spp.

Concinna

Smaller green leaves with dark green variegation.

C. roseapicta

Corona

Silver colored leaves bordered by dark green margins.

 

Cynthia

Dark green center with a 1-inch silver margin around the entire leaves and purple underside.

 

Eclipse

Dark green leaves surrounded by a silver irregular shaped pattern turning back to a dark green margin.

 

Maria

A sport of C. roseapicta. Bright silver leaves with dark green margins.

 

Medallion

Similar to Picta Royale but faster growing and more prominent silver color in the mid-rib.

 

Roseapicta

Round leaves with a solid magenta underside with two-tone green top.

 

Silhouette

A sport of 'Medallion' that has the same large, round leaves but a much brighter appearance.

 

Picta Royale

Dark purple foliage with a faint pattern of silver from mid rib to the end of the round to oblong shaped leaves.

C. rotundifolia

Rotundifolia

Dark green leaves with whitish bands between main lateral veins and paler beneath.

C. rufibarba

Rufibarba

Long slender leaves on a very upright plant. Dark green upper side with purple underside covered with tiny hairs.

C. tigrinum

Tigrinum

Large velvet-looking leaves striped with bold, alternating, light and dark green bands.

C. variegata

Variegata

Green with a median band of dark green above and paler with deeper green bands beneath.

C. vittata

Vittata

Lanceolate light green leaves with heavy white stripes from the mid rib to the leaf margin.

C. zebrina

Zebrina

Oblong light green leaves with wide dark stripes from mid rib to the leaf margin.

Table 2. 

Nutrient concentrations in leaves considered low, medium, and high for Calathea growth.

Nutrient

Low

Medium

High

Nitrogen (%)

<3.0

3.0–4.0

>4.0

Phosphorus (%)

<0.5

0.5–0.8

>0.8

Potassium (%)

<2.0

2.0–4.0

>4.0

Calcium (%)

<0.5

0.5–1.0

>1.0

Magnesium (%)

<0.25

0.25–1.0

>1.0

Sulfur (%)

<0.2

0.2–0.4

>0.4

Iron (ppm)

<40

40–200

>200

Manganese (ppm)

<30

30–150

>150

Zinc (ppm)

<20

20–200

>200

Copper (ppm)

<10

10–50

>50

Boron (ppm)

<20

20–50

>50

Table 3. 

Causes and effects of various physiological problems of Calathea.

Symptoms

Probable Cause

Treatment

Dead spots near leaf margins

Fluoride toxicity

Avoid using water and fertilizer containing fluoride.

Leaf marginal or tip necrosis

Low pH, excess fertilizer, particularly high Mn

Keep pH close to 6 and soluble salts between 1–2.5 dS/m in production and 1.0–1.5 in interiorscape. Recent studies showed that leaf Mn concentrations higher than 200 ppm was a cause of the problem.

Leaf chlorosis

Low fertilizer, over-watering, or high light levels

Increase fertilizer, particularly nitrogen and iron; reduce watering frequency, reduce light levels.

Leaf spotting and reduced foliage color

Plants take up too much potassium

Use fertilizer with an N-P2O5-K2O ratio of 3:1:2.

Wilted leaves

Drought stress or root pathogens

Keep the potting medium uniformly moist but not wet. Check root systems to determine if they are infected by pathogens or nematodes.

Footnotes

1.

This document is ENH1030, one of a series of the Environmental Horticulture Department, UF/IFAS Extension. Original publication date November 2006. Reviewed June 2016. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Jianjun Chen, professor, Environmental Horticultural Department, UF/IFAS Mid-Florida Research and Education Center; and Dennis B. McConnell, professor, Environmental Horticultural Department; UF/IFAS Extension, Gainesville, FL 32611.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.