Bromeliad tropical plants are easy to cultivate, great houseplants

Published 12:00 am Sunday, April 24, 2011

Do you know what Spanish moss and pineapples have in common? Believe it or not, they are actually related and belong to the same family of plants — the bromeliad family.

Bromeliads are a beautiful family of tropical plants, many of which posses colorful foliage, beautiful flowers or both. With their many shapes and colors and ease of culture, once you have one bromeliad you are likely to want more. But even one or two plants will make an excellent addition to your potted-plant collection.

Very undemanding and easy to grow, bromeliads’ main requirements are sufficient light, proper watering and good air circulation. Indoors, bromeliads thrive in an east, west or south window that receives plenty of light. Outside, these plants generally prefer a semi-shaded location that receives morning sun and shade from the intense light of midday and afternoon. Those with plain green leaves often require the most shade, and those with silvery or gray foliage will generally tolerate the most sun.

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Although it is an excellent practice to summer your bromeliads outside when temperatures are warm, they must be brought inside and protected during freezing weather.

Most bromeliads are grown in pots of well-drained potting mix. You won’t have to repot your newly purchased blooming bromeliad into a larger container. The container you buy it in will generally be large enough.

If you purchase a young plant that still has a lot of growing to do, however, you’ll need to repot it into a larger container as it outgrows the one it’s in. When you do, use a light potting soil with some extra perlite added, or make your own with equal parts of sphagnum peat moss, medium-grade horticultural perlite and fine fir bark.

Because most bromeliads have rather limited root systems, they are generally grown in pots that are somewhat small for the size of the plant. Clay or plastic pots are equally satisfactory as long as they have drainage holes. Clay pots are more stable because of their weight and may be better for plants that tend to be top-heavy.

The potting mix should not be kept constantly wet because bromeliads do best when allowed to dry slightly between waterings. Many species of bromeliads are able to hold considerable reserves of water in the vase-like center of the plant. This should generally be kept full of water because the leaves themselves can absorb water.

Although we generally grow bromeliads in containers for convenience, in nature these plants are typically epiphytes — plants that grow upon other plants (generally trees) but are not parasites. The water-holding, vase-like shape of many bromeliads is an adaptation to their tree-dwelling nature. Without soil to retain moisture, you can see how the reserved water held in the leaves helps the plant survive between rains.

Spanish moss, our native epiphytic bromeliad, does not produce a cup but also absorbs all of the water and nutrients it needs through its leaves. The leaves are covered by gray scales that give this plant its characteristic color. These scales trap water against the leaves until it can be absorbed. I’m often asked if Spanish moss growing in a tree will somehow injure the tree. Spanish moss makes all of its own food and derives the water and minerals it needs from rain; it is typically harmless to the tree it is growing on.

Because of their natural ability to grow on trees, you may purchase bromeliads mounted on a piece of driftwood or other material. These plants are a little more trouble than potted bromeliads to maintain and require more frequent watering — which generally is best done at the sink if the plants are growing indoors. Keep gray-leaved bromeliads well misted and the cups of others filled with water. They are worth the extra effort because mounted bromeliads are strikingly beautiful.

Bromeliads that produce attractive flowers are often purchased in bloom. The flower spikes are exotic and beautiful and usually stay attractive for an extended period of time. Some genera, such as Neoregelia, do not produce especially showy flowers, but the foliage in the center of the plant turns a brilliant color when they bloom. Indeed, for most bromeliads the flowers don’t provide the primary show, but the colorful bracts or modified leaves that accompany the flowers add to the display.

It’s important to know that after blooming bromeliad plants will never grow or bloom again. They go into a gradual decline and eventually die. Before they do, however, they produce one to several offshoots from their base called “pups.”

As the young plant grows, repot it into larger containers until it is in about the same size pot in which you bought the original plant.

Dan Gill is a LSU AgCenter horticulturist.