This week we visit the Dorothy Chapman Fuqua Orchid Center at Atlanta Botanical Garden (ABG). Ron Determan is the Conservatory Superintendent and is in charge of all facets of indoor horticulture. He also is the mastermind behind the engineering of the building. To provide the orchids a high altitude elevation environment, similar to the cloud forests of their native environment, 5 or 6 thousand feet above sea level - that of the Andes or Southeastern Asia - he has borrowed technology found in the textile industry. They use washing systems and Ron has applied it for the first time to greenhouses at ABG. He's integrated that system with other systems such as high pressure fog, cooling, roofs that open, etc.. This allows these beautiful Orchids to grow in the unlikely environment of Atlanta, Ga.
We view plants from three areas the Andes, the flat top table mountains in South America and Southeast Asia - Mount Kinabalu, the highest mountain in Borneo. We view a rock wall made with real rocks, rescued from a D.O.T. bypass. On this, Andean Mountain plants are plentiful and unusual.
The Southeastern Asian Mountain area has many plants as well. We specifically discuss Pitcher Plants, Nepenthes Lowii, carnivorous plants that grow only in these mountains.
In another area they simulate the Tepuis, the flat top table mountains in southeastern Venezuela and Brazil. The elevation in that area would be 6,500 feet or so. There are plants in/from this environment that wouldn't be encountered anywhere else on earth. One might find Carnivorous Bromeliads, relatives of Saracenias, Eucathalarias and of course, Orchids. They survive in a very thin layer of soil, a little sand and possibly a little organic matter. The soil is very well leached, practically no nutrients. The area would be wind swept and the plants hang in clouds part of the day. The roots cling to crevices in rock formations.
Becky Brinkman is the Orchid curator at ABG. She shows us some of her favorite Orchids. Cattleya Dowiana is from Costa Rica, it is a velvety crimson color with gold veins and purple margins and it has an incredible fragrance. It requires a little more light and warmth than most so she hangs it close to the glass. It could be grown in a greenhouse or atrium. We next view Coryanthes Elegantium, called a Bucket Orchid because the lip, which is the most prominent petal, is shaped like a bucket and it fills with liquid. This plant has a very peculiar pollination mechanism, it produces a powerful fragrance that attracts a particular species of bee, an Euglasian Bee. There are large iridescent tropical bees that seek this fragrance. When they land on the orchid they scratch the surface to obtain the fragrance which is a liquid. Some of the fragrance is converted into a Pheromone, some bees then loose balance and fall into the liquid and do several laps across the Orchid flower. The bee can no longer fly because his wings are wet so the only way out is through the little opening in the back and that is where the pollen is stored. By crawling through the opening the bee picks up the pollen.
Another Orchid has a different pollination mechanism. The bee lands on the Orchid that has a downward pointing antenna, almost like a trigger. The pollen is held under pressure, when the bee bumps the trigger the pollen is shot onto his back and is held there by a sticky adhesive. A tropical cousin of the Lady Slipper is Paphiopedilum Lowii. It is native to Malaysia and Indonesia. The shape of both of these flowers is similar and both like a similar environment, the forest floor, in the shade or in crevices among rocks.
Paphinia Herrerae has beautiful white, translucent petals. At ABG all are offspring of one plant brought from Equador to ABG in 1990. The ABG Orchid Center is the largest public display of Orchids in the U.S. They have a formal display area where they maintain a year round display of Orchids and flowers. Another area simulates the natural habitat of different Orchids from Mexico or Madagascar, rocky habitats, wetlands or meadows. It is all beautiful.
Mike Wenzel is Tropical Accessions Manager at ABG, that means he is in charge of cataloging and tracking thousands of plants. Mike shows us some easy to grow Orchids. The Phalaenopsis, or Moth Orchid, handles indoor temperature ranges very well. They will survive and bloom in a lower light situation although they do need light to flower. They typically bloom in the spring and some shown have largish sized flowers. Phalaenopsis Bellina is a species that you might see growing on the side of a tree in southeast Asia. It is a parent of a hybrid Phalaenopsis. It too is easy to grow, has a different style and a spicy fragrance. When watering Orchids remember they like to dry out a little between waterings. Don't let them get bone dry, but when slightly dry, soak them, then allow them to drain. Drainage is important.
Some Orchids have a bulb-like feature on the bottom called pseudo-bulbs. These organs help store water for use when water is not available. Some Orchids have these, some don't, a Moth Orchid doesn't.
Hybrid Miltonia, Honolulu tends to bloom in the summer. The hybrid shown is a beautiful purple color and has many spikes. It has the pseudo-bulbs, thus doesn't need watering often. If one wants to get the plant to rebloom, fertilizer is not necessarily the answer. Often times light is the biggest issue, Orchids don't need full sun, but they do need bright indirect light in the morning, particularly if the plant is behind glass. They can be taken outdoors as long as they don't get too much light, especially in the afternoon, or too much water. Bright indirect light is ideal.
Miltassia is a hybrid, has a completely different look, almost spidery. It has a lot of browns, maroons and mauves and is exotic looking. It too is easy to care for.
Becky Brinkman joins us again to show us how to repot Orchids. Repotting an Orchid is easy. Remember Orchids resent root disturbance. Their roots are designed to attach to surfaces, typically a tree trunk. They also attach to the inside of a pot. When they're repotted the roots tear from the surface - the pot - and that results in injury and a setback for the plant. There are two reasons to repot an Orchid. One is if the plant has outgrown the pot, the second occurs when the soil mix has broken down. Becky has assembled all materials needed to repot- sterile sharp cutting tools, clean pots rhizome clips and soil mix. The soil mix contains no soil but instead fir bark, charcoal and lava rock, otherwise known as Perlite. The best time to repot is when the new shoot is 1 to 2 inches tall, before the roots have emerged. Keep your eye on the new shoot because it is as tender as new Asparagus and if you break the new shoot you've lost a whole years growth. First remove the Rhizome clip from the pot, invert the plant and gently tap it on the table. Next wash the roots, this removes old soil sediment from the root ball and allows examination of the roots. In the case of the plant in this show the older part has started to die back. It no longer has living roots. Remove that portion of the plant, Becky uses the razor blade and removes the oldest three growths from the plant. The roots were no longer healthy. she then chooses the correct size pot. Orchids like to have their roots confined in the pot, not so much because they like confinement but because they like their roots to grow on the pot itself. Make sure the plant is snug in the pot yet still has enough room to grow for two years. To make room for two years growth, place the plant, not in the center, but back the old growth against the side of the pot. This allows the new shoots room to grow. Fill in the empty space with the soil mix, packing it firmly insuring no air pockets. Make sure the plant doesn't wobble. Once done, attach the Rhizome clip. It holds the plant firmly in place. Fertilize every two weeks, watch for pests and the plant should be good for another two years.