What Is a Cryptanthus?

(Taken from The BromeliAdvisory - December 2004)

Named from the Greek krypte, "hidden," and anthos, "flower," these plants,
members of the family Bromeliaceae, are related to the pineapple. Their common
name, 'Earth Stars,' came naturally from the way their low, spreading rosettes
hug the ground "like fallen stars." The variability of shapes, colors, and patterns,
plus their adaptability to a wide range of growing conditions, make Cryptanthus
a favorite of plant lovers around the world.

Potting

Cryptanthus in their natural habitat are true terrestrials ( Growing in the earth ).
A few varieties are saxicolous ( growing in soil pockets among rocks ), but none
have ever been observed growing as epiphytes ( growing on other plants, but
receiving nourishment from the air). Cryptanthus should always be growing as
potted plants.

The growing medium should be a loose, porous mixture. There are many good
mixes: commercial potting soils, African Violet mix, soils mixes or a mixture of
peat and sand with perlite. Regardless of the mix chosen, it must be kept damp
for best growth. It should never be allowed to totally dry out. Plastic pots help
conserve moisture. Successful growers have used capillary matting, wick
watering, misting systems as well as the old-fashioned method of watching the
plant and giving it a drink when needed.

Cryptanthus should not be under-potted. The develop root systems at least equal
to the size of the plant - a five or six inch pot will allow the root system plenty of
room to develop.

Light

In their native habitat of Brazil, Cryptanthus can be found growing in a wide
variety of conditions; sunny, shady, moist, dry, in forests, and at the ocean side.
There is a Cryptanthus variety to fit any light condition. C. beukerii and it's hybrids
like to be shaded, moist and humid. They are excellent for terrariums. Species
such as C. bahianus sp 'Cascade', and C. warasii will tolerate full sun, but the
plants grow better in diffused light. Too much light causes bleaching, sunburn, or
gives a leathery stressed look to the plants. Bright, diffused light is necessary to
bring out maximum color in most Cryptanthus.

Lack of enough light will result in dull uninteresting foliage. "Greening" of a
usually colorful Cryptanthus, or weak unbalanced growth, is usually caused by
insufficient light, proper lighting will bring out the best in Cryptanthus.

Acclimate plants to grow in as much light as possible. The light source may be
natural ( in the greenhouse, outside with strong, but filtered light, in a windows
garden ) or artificial ("grow lights" or plant carts ). Cryptanthus grow equally well
with either.. The colors intensify under fluorescent light, which make Cryptanthus
an excellent choice for office decorating.

Whatever the light source, be sure plants receive even lighting. If the light comes
from only one side ( as in a window garden, be sure to turn the plants regularly
to promote balanced growth.

Temperature

Cryptanthus prefer the same temperatures as their growers. Optimum growth
occurs in a range between 60 and 85 degrees Fahrenheit ( 16 - 29 degrees
Celsius ). However, Cryptanthus will thrive in less than optimum conditions.
Outdoor gardeners will be please to learn that most Cryptanthus can withstand
temperatures just above freezing and some varieties will survive winter outside
if they are heavily mulched and the root zone does not freeze. If one wishes to
leave plants outdoors over the winter, they should be "hardened off" in the fall
by cutting back on the amount of water they receive. Depending on how long the
temperatures remain below freezing, leaf damage may be severe, but the mulch
protects the root zone and spring brings renewed growth. On the other extreme,
Cryptanthus are very tolerant of high temperatures, even above 100 degrees ( 38
degrees C ) as long as there is adequate humidity and potting mix is not allowed
to dry out. Again they should be protected from the scorching effects of direct
sunlight.

In temperate climates, Cryptanthus grow easily and well outdoors, making beautiful
and exotic bedding plants or ground cover. In colder climates, one might consider
growing potted Cryptanthus outside during the warmer months. The pots can be
sunk into the outdoor garden for the summer, and then easily removed to a safe
winter inside, beautifying your home or greenhouse. Cryptanthus grow just as well,
or even better in the year-round controlled environment of an indoor garden.

Humidity

Many Cryptanthus varieties enjoy high humidity which may be increased in the
home or office with the use of humidifiers, frequent misting, capillary matting,
by placing the pots over water, or grouping plants together. Cryptanthus make
wonderful accent plants in well-lit bathrooms or above the kitchen sink where
the humidity is generally high.

Fertilizing

Fertilizer is not necessary for Cryptanthus to show off their dazzling colors, but
it is necessary for maximum growth. A timed release balanced ( 14-14-14, 10-10-10)
fertilizer combined in the potting mix gives excellent results. Other types of
fertilizer such as African Violet, Orchid or organic, used in a diluted form with
each watering, work equally well. Like people, Cryptanthus require proper nutrition.

Blooming

Although the name Cryptanthus means hidden flower, many varieties flatten,
at maturity to reveal a bouquet of delicate flowers. Some varieties maintain
an upright growth with the flowers remaining somewhat hidden, while others
actually bloom on a scape ( stem ). Some varieties display one flower at a time;
others exhibit an entire cluster at one show. As different species and cultivars
bloom at different times of the year, it is possible to have different varieties in
bloom the year around. They are reliable bloomers - there is no need to force
bloom Cryptanthus.

Offsets or Pups

Each Cryptanthus plant blooms only once in its lifetime. But after it blooms, it
will reward you with new plants! Beginning before or immediately after
blooming, Cryptanthus will produce offsets, or pups - new plants - which form
from the axils, from woody solons ( as with C. bahianus), or from the base of
the parent plant. One will have the beginning of generations of plants to keep
or share with friends.

Offsets may be left on the mother plant for multiple growth. The ideal hanging
basket plant, sp. 'Cascade' produces long, hanging stolons of up to two feet with
rosettes ( pups ) forming at the ends. Other varieties will form clumps or mats of
beautiful color. If one wishes to remove the offsets, allow them to grow to about
one-quarter the size of the mother plant. Then, a slight tug will easily detach the
offsets from the mother plant. Some varieties release their own offsets when they
are sufficiently mature. Don't be alarmed that there are no roots on the pup. In
nature the pup would roll to a new location or take root in the decaying humus
around the mother plant.

Cryptanthus will root easily in potting medium. Make a small depression, insert
the pup's small stem and press the mixture firmly around it. Pot no deeper than
the base of the first leaf. Stake the plant if necessary to keep it from rocking
back and forth. It is essential for the plant to be secure for an extra fast start
and good growth. Bottom heat may speed root development in colder climates.
Place the newly potted plant in a favorable location and water it as one would
a mature plant.

Insects and Disease

Cryptanthus are relatively pest-free. By following good horticultural practices
severe problems can be avoided. Two of the more common insect problems
that may be encountered are mealy bugs or scale. Scale is a destructive insect
which forms and remains under a waxy scales on the plants. If either are found
on Cryptanthus, treat the infected plants with any insecticide recommended for
use on houseplants. Wear gloves, follow the manufacturer's instructions for mixing,
and dip the entire plant in the insecticide.

Fungus is the most common disease found in Cryptanthus. There are many good
fungicides available. In an area where fungus is a problem use a fungicide regularly.
After any treatment, keep the plant in the shade for at least 4 to 24 hours. Then
rinse it thoroughly, but do not place it in bright light until the leaves are completely
dry. With any severe infestation or disease, infected plants should be isolated until
the problem is corrected. Cryptanthus should also be protected from contact with
galvanized metal, copper and pre-treated wood.