Thursday, February 1, 2007

Let's Get Terrestrial

Terrestrial orchids occupy a strange space in the indoor orchid growing world. They come from a wide variety of genera, their growth habits run from miniature mat forming growths to giant upright fans of foliage, and cultural requirements vary from outdoor hardy bulb-types to rainforest shade growers.

And then there’s that whole dirt thing. For many orchid growers, the idea of growing orchids in regular plant potting mix seems downright odd; a step back towards growing those boring old houseplants that many of us nurtured our green thumbs on before graduating to orchids. Where’s the challenge? Actually, terrestrials give the indoor grower a large number of worthwhile and rewarding orchids to grow, and ease of culture doesn’t have to be a drawback!

Rather than discuss terrestrials according to their taxonomic classifications, let’s divide them into a few very unscientific, but more user-friendly categories:

  1. Small bulb growers

  2. Jewel orchids

  3. Clumping terrestrials

  4. Larger terrestrials

Small Bulb Growers

Bletillas and pleiones are two orchid species often found in garden catalogs alongside familiar bulbs like tulips, narcissus, and daylilies, but they are orchids, and there’s no reason not to grow them indoors. First, they’re really small: you can keep three bulbs in a four inch pot. Second, during the winter, you don’t have to take care of them at all – just clean off the bulbs at the end of the growing season in the fall, put them in a paper bag with some barely moist sphagnum moss, and put them in the back of the refrigerator – yes, you heard that right! They need a cold, but not freezing period to initiate blooming. After about 2-3 months in the crisper, take out the bulbs, pot them in fine bark with some regular plant potting mix added, and water when new growth appears

Ancistrochilus rothschildianus doesn’t need refrigeration , but it does need some attention to watering in order to grow well. It is deciduous, so when its leaves start to die down in the fall, it’s time to cut back on water, but not let it dry out completely. Its small bulbs have been described as looking like “little chocolate kisses”, and it bears bluish/mauve flowers in the spring that are large for the size of the plant.

Spathoglottis is often used as a landscape plant in frost-free areas, it does not go deciduous but needs even moisture and medium light. It has wide, pleated leaves, and happy plants can bloom almost year round.

Jewel Orchids

Jewel orchids are named for their brightly patterned leaves, often with veins of bright red, or sparkling gold or silver tones. They are grown as foliage plants rather than for their flowers, which are usually small and undistinguished. They are rainforest understory plants, meaning they like it warm, humid and shady, perfect for a small terrarium or a shady window. They prefer a mix with lots of leaf humus, peat and chopped sphagnum moss, to mimic the leaf litter and moss of their natural habitat. Their leaves can be marked or even rot due to water remaining on young leaves, especially in cold weather: water carefully at the level of the pot rather than drenching from above. The most common jewel orchid is ludisia (haemaria) discolor, with dark, almost black leaves veined in red. Despite its exotic leaves it’s a pretty tough plant, able to grow in lower humidity and drier mix, and can be propagated simply by rooting pieces of stem in water. It also has an alba variation, with green leaves veined in white, and the rarer var. dawsonia with only one central red vein. Also available is macodes petiola, with fabulous bright and dark green dappled leaves veined in gold – a bit trickier to grow, but well worth the effort. Less available genii include anoectochilus, with some of the most beautiful markings of the group, goodyera, which has both tropical and hardy species, stenoglottis fimbriata and hybrids, with purple spotted leaves, cyclopogon, some malaxis species, sarcoglottis, stenosarchos, and even some oeceoclades species. If you can’t find any of these, take that paphiopedilum that’s never bloomed for you, put it in a fancy pot, and call it your jewel orchid.

Clumping Terrestrials

Clumping terrestrials are a diverse group of orchids that, well, clump. But don’t yawn! There are some great orchids in this bunch –

Habenaria rhodochila is a small grower with spotted leaves almost as pretty as a jewel orchid’s, and it bears numerous flowers in shades of white, yellow, orange or red. Oeceoclades maculata also has attractively mottled leaves; its flowers are small and white with pink markings.

Liparis has some terrestrial species, they generally have spikes of small, but often highly colored flowers; an established specimen can put on quite a display.

Malaxis is similar to liparis in its growing requirements and habits; some species have pretty pleated or marked leaves.

Large Terrestrials

Larger terrestrials include some really showy, outstanding species that make fabulous indoor pecimens. Take phaius tankervillae, which produces spikes of up to 20 3 inch flowers in shades of rose, tan and white, and has large pleated leaves which give a tropical look to any room. It can get quite large, so also look at phaius Bebe Chien, a hybrid with the smaller growing phaius pulcher, or the increasingly popular phaiocalanthe hybrids like Cryptonite or Dan Rosenberg.

Calanthes are also worth growing in their own right. Some species are like the smaller bulbous growers, ideciduous in winter and needing no more care then your summer sandals. However, others are evergreen, and need to be kept moist all year round. All have long spikes of flowers in all shades from white to dark red, which make excellent cult flowers.

Next is sobralia, a genus of South American orchids with leaves and growth habit much like bamboo. Their flowers look like cattleyas, and last only one day, but are produced successively during the blooming season, so that a mature specimen can put on quite a display. Smaller species like callosa, powellii and decora only grow about 2-3 feet tall indoors, while larger species like macrantha can top out at over five feet – just the thing to screen a bare stretch of wall. Sobralias, like phaius, like lots of water and fertilizer during the growing season, less in winter, and bloom best when potted tightly.

Arpophyllum doesn’t grow as tall as sobralia, but it does have a spike up to 4ft., with a tight cluster of small purple flowers that remind many of grape hyacinths. It needs excellent drainage, with lots of tree fern and sphag in the mix, and medium light.

Last, but not least, in our line up is thunia, a genus that has a habit like sobralia, but loses its leaves and goes completely dry and dormant for the winter – put it away, it looks like a dead dendrobium. Come spring, though, new growth shoots up at a fantastic rate, and blooms successively with white, cattleya-like flowers. It’s also one of the only orchids in the world that features attractive fall foliage – the leaves color golden brown before dropping!

That’s it; have fun going terrestrial!


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