Orchids from Aerial Cuttings

Wednesday, February 29, 2012
Propagating Orchids II Last week, I blogged about propagating orchids using divisions and back bulbs. These two methods are very popular, but there’s more: I was introduced to orchid keiki in the lava fields on the Big Island during my ill-fated stint in Hilo. I was in the right place at the wrong time, and only a few days were spent in glorious exploration of this rare and wonderful environment. Thankfully, one day was devoted to Hawaii Volcanoes National Park, home of Kilauea, one of the world’s most active volcanoes. Arundina orchids are among the first plants to sprout when the lava cools after an eruption and dot the black soil like prayer flags. The plants are tall, a weedy pest in the Tropics, and very prone to reproduction. The day I walked among them, I noticed that a few of the plants were multi-branched candelabras, but most had 2 or 3 stems and swollen nodes. A closer inspection revealed those nodes to be the beginnings of new plants, or keiki. This rampant reproductive nature of Arundina has made it a pest in some places, but you have to admire a plant that will not be stopped and constantly insures its future. It’s got spunk, and I like it. Just a side note: I grow other plants that are considered bullies, like the Clerodendrum known as Mexican hydrangea or Kashmir bouquet, but do avoid the real invasive species like Chinese tallow. I certainly would not plant Arundina outdoors in a tropical environment, I promise, but its reproductive abilities should be an inspiration to other, more finicky orchids. Not only Arundina produces keikis; Phalaenopsis, Dendrobiums, Epidendrums, and Vandas also make them. Here’s how: Orchid stems can and do branch, sending secondary shoots out of their nodes. Sometimes a small plant sprouts there called a keiki. They are perfect copies of the mother plant, natural or sometimes induced babies, or keikis in Hawaiian. Correctly pronounced, it is ‘kay-ee-kee’, but most Mainlanders say ‘kay kee’ without pronouncing the middle syllable. Whatever you call them, these babies are cute and ready to grow slowly into plants with roots that are large enough to clip off and pot up. Be patient! This process can take six months, aided by your intentions and basic good care of the mother plant. As the roots begin to show, mist them lightly once a week with a solution of Hormex Liquid Concentrate mixed 10 drops in a gallon of water. Take care when removing keiki orchids so the roots are not damaged. Cut the keiki away from the mother plant with an inch or 2 of stem on either side of it. Use that stem to help stabilize the orchid in its new pot. Water weekly with a solution of 1 teaspoon/gallon of HLC and water. Remember, keikis grow slowly but usually flower the second year. Orchid plants often produce flowering canes, including many Dendrobiums. They can sprout aerial shoots on back bulbs that lack leaves. Small plants develop there, similar to piggyback plant or airplane plant, but over a longer period of time. If a stressful event occurs, such as overwatering or excessive drought, canes can also fail to bloom and may produce small plants where you would expect flower buds. These aerial shoots will form roots in about 3 months and can be clipped from the mother plant (along with a portion of the back bulb if necessary) and potted up. The roots that form in air must be nurtured in the transition to life in soil, and will benefit from weekly watering with Hormex Liquid Concentrate mixed 1 teaspoon to a gallon of water. Two other methods are used to propagate orchid: tissue (or meristem) culture and seeds. Both demand sterile conditions, so are seldom used at home. Seeds are preferred by those who want to see how diverse the results can be, and some of the finest selections known today were once random seedlings. Tissue culture grows slivers of meristem to produce glass tubes full of tiny plants just like the plant that donated the tissue. It is much cheaper to produce plants this way once the dear initial costs are recouped, and has made it possible to ship thousands of orchid plants in a small box from a commercial propagator to a finishing grower. When the horticultural history of the 21st century is written, I believe that one of the benchmarks will be the geometric expansion in the availability of orchid plants, thanks to tissue culture. Long ago and far away, I worked with tissue culture briefly in a research environment. My fellow graduate student wanted to facilitate the delivery of cabbages and other vegetables to growers in her Asian homeland. She found her way of choice in meristem culture, and the rest of us got to explore what was, at the time, new-fangled technology. It’s true what they say – if you’re looking for a fascinating field that takes you from the backyard to state-of-the-art laboratories and runs the gamut of potential careers, you should consider horticulture.
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