Bromeliads in the genus Alcantarea are native to eastern Brazil, where they grow terrestrially in open places. Most of them grow in full sun, on granite outcrops (inselbergs) that can soar up to 500 ft. above rivers, tropical forests, and cultivated fields in cracks where water percolates through the granite. Many of them were formerly in the genus Vriesea. Most are very large--3 to 5 ft. in diameter at full size--and have brightly colored, lightly colored, or white and green inflorescences that are spectacular. The inflorescences can be up to 7-8 ft. tall, with multiple branches; large, sometimes colorful bracts; and lovely, three-petaled, yellow or white flowers with long, protruding stamens. Many have flowers with long petals that curve backward and sideways, like lovely curls at the ends. Don't hold your breath waiting for these plants to flower--they can be 10 or more years old before they flower. But it's worth the wait!
You will need space to grow these plants. Alcantarea species can be grown in a loose mix of potting soil, a little charcoal, and perlite. Increase pot size as they grow.
They eventually become so heavy that the bases lean and press against the edge of the pot. At this time, they'll fall over when loaded with water unless some preventative measure is taken. I usually pot them in plastic pots and place those pots into heavy clay pots. Sometimes I also need to counterbalance the base of the plant by putting a brick or two in the plastic pot on the side opposite the plant base. Some species and varieties (e.g., A. imperialis 'Red') tend to rot at the base; to guard against this, grow those plants in pure perlite and porous rock (e.g., commercially available lava rock (1)), with lots of time-released fertilizer (avoid placing the fertilizer so that it touches the plant base).
They respond well to time-released fertilizer (I use 6-month time-released Nutricote, also available as Dynamite). They also do well in the ground. If covered with light frostcloth or sheets, they survive light frosts without damage. I grow them in my yard, in full sun or partial shade, and in a shadehouse sitting high above all other plants. Plant or place them in locations where you won't need to move them after they're full-grown. An alcantarea holding even a little water can weigh 80-100 lb.
The pups on alcantareas grow from the trunk. Small "grass pups" with thin leaves can appear beneath the leaves when the plant is small through full-sized. These can be removed when they're about 4-5 in. long and potted. They are not easily removed because the base is recurved into the trunk of the parent plant. To remove them, dig the potting mix away from the plant, grasp the pup by the base, and wiggle it from side to side while simultaneously pulling the pup a bit away from the mother plant. Very robust pups frequently appear after the plant has bloomed (cut off the inflorescence) if time-released fertilizer pellets are placed between the leaves. Sometimes it's possible to get a dozen or more pups by using this method. To remove those pups, I remove all leaves below them and use the same technique described above for the grass pups. The best way to get them to root is to insert them between the parent plant's trunk and a big remaining leaf until they develop roots, which takes a few months. For me, that works better than potting them.
Few bromeliad enthusiasts here seem to grow Alcantarea species, probably because they are so big, but if you want unique, interesting landscape, try plants of this genus. They can tolerate some leaf litter accumulation, but not acorns or rotting leaves left in their centers for months. Several large species available for cultivation are cold-tolerant, easy to grow, and spectacular (e.g., Alcantarea imperialis, A. odorata, A. extensa, A. brasiliana, A. vinicolor, and A. heloisae). A. imperialis, the most popular species, comes in several colors. The broad, stiff, spineless leaves are green above and green or various shades of red or purple beneath. A. odorata can be purchased with varying degrees of trichome (scurf) coverage. Those with thick coverings (e.g., cultivar 'Silver') are fuzzy, or snowy-looking, and interestingly beautiful.
(1) also called "scoria" in some counries--Ed.
Theresa M. Bert. BSI Director, Florida. Photographs by Birgit Rhode.
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|Author:||Bert, Theresa M.|
|Publication:||Journal of the Bromeliad Society|
|Date:||Sep 1, 2007|
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