Tropicals, Woody > Alcantarea > Alcantarea imperialis (Carrière) Harms > Alcantarea imperialis (carrière) harms
Alcantarea imperialis (Carrière) Harms
Giant bromeliad, Imperial bromeliad
Origin: Endemic to Brazil, occurring in the Atlantic Forest in the states of Rio de Janeiro and Minas Gerais. Due to its value, commercial interest in landscapes and to the possibility of fires on natural subpopulations, there is a risk of a local extinction.
Mike's
Opinion
"
Alcantarea genus represents the giant’s Brazilian bromeliads, reaching 5 meters height when bloom. This genus has a great interest to naturalists, collectors, horticulturists and for the entire ecosystem as most species keep a considerable volume of water between their leaves providing an important reservoir for fauna, being home for frogs and insects or even some aquatic plants. It is considered an evergreen plant in the Tropical Forests, being one of the largest bromeliads of the world. It can survive to cold temperatures in this area, supporting up to -3°C, but the plant was not exposed to stronger frosts. - Carolina Gerbelli
Michael Pascoe, NDP., ODH., CLT., MSc. (Plant Conservation)
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| Family |
| Bromeliaceae |
| Genus |
| Alcantarea |
| Species |
| imperialis (Carrière) Harms |
| Category |
| Tropicals, Woody |
| Type |
| Tree (evergreen) |
| USDA Hardiness Zone |
| 9 a - 11 |
| Canadian Hardiness Zone |
| Requires cold season protection under glass. |
| RHS Hardiness Zone |
| H4 – H1C |
| Temperature (°C) |
| (-6.7) – (-3.9) |
| Temperature (°F) |
| 20 - 25 |
| Height |
| 5 m |
| Spread |
| 90 – 120 cm |
Photographs
Cultivars
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Description and Growing Information
Flowering Period
| General Description |
| An herbaceous plant, native to Brazil, perennial, erect and robust arranged in a rosette. Its shape is large with varieties of red, purple, and green foliage, in addition to intermediate shades of colours. It has a unique inflorescence that is erect, branched, and can reach 3 to 5 meters in height. Flowers are delicate yellow, with long creamy-white stamens, with reddish bracts, being attractive to pollinators. Flowers appear after 8 years, when the plant is mature and can last up to 12 months. It is a monocarpic plant, flowering once in a lifetime and then dies. When the bromeliad has finished blooming, it will form “pups” at the base of the plant which, when they are large enough, can be removed and replanted. |
| Landscape |
| Very desired by landscapers, as it’s considered unique for its size, has beautiful colours and even because it is an endemic plant in Brazil. In the garden it is usually planted alone as a focal point or in groups. It is welcome to be planted with rocky outcrops or with other bromeliads species. In practice, some people also plant it in containers. One important issue to be considered is to assure the origin of the plant, it must come from a mother plant or in nurseries certified by IBAMA – Brazilian Institute for the Environment and Renewable Natural Resources. It is considered a houseplant, used in house gardens or commercial buildings as it is resistant to winds, light frosts, pests, and diseases. |
| Cultivation |
| The plant might grow in any medium moisture that dries well and provides stability for the rooting system with a slightly acidic (6.0 – 6.5) to neutral pH (7.5). When planting in pots, some materials can be used either alone or in combination as perlite, coarse builders’ sand, tree fern fiber, small gravel, and red wood, pine, cypress, or fir bark. It is not recommended to plant it too deeply. Being the best condition for most species of bromeliads it grows best in full sun, bright and diffused light. When the plant doesn’t receive enough light, the leaves will become dark green, on the other hand, too much light will turn the leaves yellow. This plant can grow successfully under artificial light, fluorescent light being best due to its intensive light and less heat. Humidity and air circulation are also important, especially if you are cultivating it protected under glass. It can be considered as humidity, drought, and salt tolerant. |
| Shape |
| With a large form, Alcantarea imperiallis is a stem, with long and broad, leathery leaves, with a waxy surface, arranged in a rosette and forming a “vase” in the center of the plant, where it accumulates water and nutrients. It can reach about 1.5 meters in diameter as an adult. Its roots are strong and fibrous, and it is important not only to nurture the plant but mainly to fix on the soil. This feature allows Alcantarea imperialis to fix on vertical rock walls. |
| ID Characteristic |
| It is very easy to identify a bromeliad due its rosette shape, forming a cup in the center of the plant. In addition, its large form with large and leathery leaves with different variety colours from green, purple, reddish and intermediate shades of those colours. The flower is also very distinguished, it is shaped like a spike and can reach more than 3 meters in height. It has reddish-brown bracts and flowers with long, cream, or yellow stamens. |
| Pests |
| Relatively pest free, however if bugs or scales are present, due to the shape of their leaves it is very easy to eliminate it just by carefully brushing the leaves. It is also important to protect the center of the plant, avoiding leaving any insecticide in the cup. Fungus is not a common problem on this plant either. |
| Habitat |
| Considered as an evergreen perennial, it naturally grows in the Atlantic forests, on rocky outcrops and mountain formations in the Southeast Region, in the cities of Rio de Janeiro and Minas Gerais. Alcantarea imperialis establishes its own micro habitat providing a store of water and nutrients in addition to the reserves held in the leaf bases and vases. Due to the high altitude this species can withstand relatively cool nights and light frosts. |
| Bark/Stem Description |
| The stem is developed and robust. From the stem, lateral shoots emerge that can form small clumps of young individuals around the mother plant, isolated shoots, separated from the mother by a short stolon or may emerge from the axil of the peripheral leaves of the rosette. It is important to mention that bromeliads also have leaf sheaths that can be oval, oblong, or trapezoidal. |
| Flower/Leaf Bud Description |
| This plant presents a panicle inflorescence and can measure 3.5 meters in height, with a reddish-brown bract. |
| Leaf Description |
| Apex of the blade foliar might be acute to obtuse and the colour of the blade foliar variable between green and wine-coloured. The form of the blade is ligulate and the form of the rosette infundibular. The margin foliar maculate or with thin line wine-coloured or purple present and there is presence of the wax epicuticular variable of the shiny to waxy. One interesting characteristic is when the plant is mature you might notice a silvery white powder on the top of the leaves. |
| Flower Description |
| A slower growing imperial bromeliad on average takes 10 years to reach full size and start flowering. Its inflorescence is shaped like a spike and can reach more than 3 meters in height. It has a very rich flowering for pollinators, such as hummingbirds and bees. It also has reddish-brown bracts and flowers with long, cream, or yellow stamens. The imperial bromeliad blooms only once when they reach adult size, as well as others, they last about twelve months. Strong changes in growing conditions, such as light or excessive dryness, may trigger a mature plant to bloom. Flowering happens during the summer and late summer. (November to March in South America). |
| Fruit Description |
| Fruit is a septicidal capsule, weighing between 0.9 to 1.3 grams with numerous seeds (around 300 seeds). |
| Colour Description |
| Its foliage has vibrant colors passing through green, red, and purplish tones, having a characteristic of brownish red on the underside of the leaves, in addition to intermediate shades of these colors. Flowers are delicate yellow, with long creamy-white stamens, with reddish bracts, being attractive to pollinators. As an evergreen, the colour will be the same throughout the seasons, the only thing is that when the plant is mature a white silver powder may be noticed on the leaves. |
| Texture Description |
| Texture may keep the same during all the seasons, the long and broad leaves are leathery with a waxy surface. |
| Notable Specimens |
| The Royal Botanic Gardens Kew located in the United Kingdom has a beautiful specimen. |
| Propagation |
| In general, there are two ways to propagate the plant. The first one is asexually, after the plant has bloomed, it will very slowly die over the next year or two, but it will replace itself with new plants called pups, offsets, or offshoots. Most pups grow off the side of the mother plant at the base. Just remove these pups when they are about 1/3 to 1/2 the size of the mother plant and replant it. The second option to propagate is by seeds, however, due its long period of flowering and uneven ripening of the fruits, propagation by this method is not often used. Flowers bloom from November to March, the fruits are ripe from June to August, and then the seeds are released. If the seeds are collected, they must be washed and drained before being germinated. Several studies show that it takes more than a hundred days to germinate, being a very rare method of propagation. |
References
Versieux, L. M. (2021) Alcantarea. Giants Bromeliads from Brazil. 2nd Edition. Publisher: Capim Macio.
Bromeliad Society International. (March 2022). Bromeliad Culture Brochure. https://www.bsi.org/new/
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