(cript – anth’ – us)
The name Cryptanthus is derived from the Latin word crypt meaning “hidden” and the Greek word anthos meaning “flowers”. The name is not completely accurate. The small, white, stemless flowers are far from hidden; they might not be flaunted like those of a Guzmania or Aechmea, but perched in the middle of a relatively flat plant they are far from hidden. Their nickname, Earth Stars, is probably more descriptive. Most species are small monolayered plants with little leaf overlap; they look like twinkling stars.
The first Cryptanthus species were discovered in eastern Brazil about 1831. The first documented hybrid, Lubbersiannaus ( bivittatus X bahianus or beuckeri ), was made by Jacob-Makoy in 1884. Although Walter Richter did some work with Cryptanthus in the 1930′s, and Mulford Foster in the 1960′s, the genus was more or less ignored until the 1970′s when Hummel in the United States and Grace Goode in Australia kicked off a hybridizing frenzy that continues to this day.
All Cryptanthus belong to the subfamily Bromelioideae. Almost all of the species in this genus are found in Brazil. They are all terrestrial plants that can be found growing in almost any condition; in the sun, in the shade, in wet areas, and in dry areas, at sea level or high in the mountains. Most plants consist of a large root system and a low spreading rosette of 5 to 20 leaves. The leaves can be mottled or striped, and they come in brown, rose, green, silver, gray, copper, pink, white, or red. Most plants are small, ranging in size from lacerdae which is about 4 inches across to a large bahianus or fosterianus that can be 18-24 inches across.
Most like low to moderate sunlight (65%-75% shade which is about 2500 to 3500 foot candles). Too little sun and they do not color up; too much sun and their colors bleach out. Species like beuckeri with thin leaves will turn brown and die in intense light, but other species, such as bahianus and warasii, enjoy almost full sun. Cryptanthus grow well under artificial light. A two light fixture will suffice, but for optimum growth a four light fixture should be used. They will grow under a 50/50 mix of warm white and cool white bulbs, but the best results are usually obtained when grow lights are used. The plants should be placed 4 to 6 inches away from the light bulbs.
They prefer temperatures in the range of 55-65 degrees Fahrenheit at night with the temperature rising to 70-90 degrees in the daytime. The nighttime temperature should be 10-15 degrees lower than the daytime temperature. Some species can tolerate temperatures as low as 34 degrees Fahrenheit for short periods of time, however some damage will occur. High temperatures, over 100 degrees, will cause bleaching, but if the plant is well watered it will usually recover rapidly when the temperature moderates.
A slow release fertilizer added to the mix when potting pups will get them off to a good start. Well established plants growing in bright light can be fertilized at every watering with dilute (¼ strength) general purpose fertilizer. Cut back on the fertilizer if the temperature or light is low. Too much fertilization can lead to oversized plants that are susceptible to insect and disease damage. Foliage feeding a Cryptanthus is a waste of good fertilizer, because their leaves lack the ability to absorb water and nutrients.
These plants like to be treated similar to an African violet; not too wet, not too dry; they want to be evenly moist. Soggy plants rot, dry plants shrivel and die. To supply the constant supply of moisture that these plants require, you can water on a regular schedule, or they can be water wicked or placed on a capillary mat. Misting doesn’t help these plants other than providing humidity, because the trichomes on Cryptanthus leaves do not absorb moisture or nutrients.
Use a mix that holds more moisture than the standard mix, but it still must be well drained. A peat based soil less African Violet mix with some water-retaining polymer added makes a good medium. If you want to experiment with soils, be creative. One such creative mix is 4 parts Canadian peat, 1 part vermiculite, 1 part perlite, 1 part sharp sand, 1 part composted cow manure.
Smaller plants will grow well in 4 or 4.5 inch pots, however the larger varieties are best potted in 5 or 6 inch pots. Plastic pots are preferable to clay pots because plastic pots are lighter and hold moisture for a longer period of time. Cryptanthus are shallow rooted so an azalea pot is deep enough to accommodate the plant’s root system. You can use standard pots, but they take more soil to fill, have a higher center of gravity, and dry out faster.
You can grow plants from seed, but starting with a pup is quicker and easier. Near blooming time plants produce pups in the leaf axils, on stolens, or from the base of the plant. When the pups are 1/3 to 1/2 the size of the mother plant give them a gentle tug; if they separate easily, they are mature enough to survive on their own. Pot the pups in the same sized pot using the same type of mix that the mother was growing in. The pups usually will root faster if you remove any brown lower leaves, and treat the exposed portion with a rooting compound.
Properly spaced plants growing in a well ventilated area are seldom bothered by disease or insects. Occasionally a plant will be attacked by a fungus, but recovery is rapid when treated early with a fungicide. Insect problems are usually restricted to the occasional grasshopper or slug bite, although Mealybugs can be a problem when growing indoors.
Almost any Cryptanthus (with the exception of a few of the specie plants) will grow well in the Houston area. Some of the more popular are species are:
acaulis, bivittatus, bivittatus ‘Pink Starlite’, bivittatus ‘Ruby’, beuckeri, fosterianus, fosterianus ‘Elaine’, marginatus ‘Arlety’, ‘Ti’, zonatus, zonatus ‘Nivea’
Some of the more popular are hybrids are:
‘Fire and Ice’
‘Green N’ Red’
The following species are sun lovers and will take very bright light (40%-50% shade cloth) when properly acclimated.