GREENGOLD GARDEN CONCEPTS
CARE AND MAINTENANCE NOTES

NATIVE ORCHIDS

Hide-away orchids so tiny and green That, mingling with grasses, they scarce can be seen:

And party-dress orchids like bush-fairies sweet- Scraps of bright magic at play round my feet.

-Nuri Mass

Orchids belong to largest family of family plants - Orchidaceae, classified the highest form of plant life. A very variable, adaptable family, it has 600 genera - more than 20,000 species! Orchids occur mostly in tropical regions put can be found in almost every climate from the slopes of Mt Everest to very arid lands. Of the 90 genera, over 600 species, found in Australia, most occur in coastal areas with some inland locations, the larger numbers in the northern and upper eastern regions.

"The reason for this enormous number of species is the proliferation of specialised forms in the family. There are probably more specialists among the orchids than among the plants of any other family, each one of them designed to ensure successful pollination by particular insects. These variations have produced blooms that are sometimes beautiful in colour and texture, often astonishing in the precision of their structural adaptations, and always individually unique. It is impossible to be bored by orchids." - Densey Clyne, "Australian Rock and Tree Orchids"

"Now what is it about an orchid that makes it different from other flowers? Firstly, instead of having the usual ring of stamens with a pistil in the centre, an orchid has a "column" which carries both the male and female parts. Then, in a great many orchids, one petal is so different from the others that it has a special name, "labellum", or lip. And there seems to be no end to the ideas that orchids can get when it comes to their labellums. They have them fringed furry or bearded, beautifully coloured and decorated. Yat sometimes for a change, the labellum can be quite a lot smaller than the other petals - almost like a little curved tube. And again, for a change, it can sometimes behave like a playful trap, imprisoning the bee long enough to make sure he brushes against the column to collect pollen. Also, in orchids the sepals are not green - but coloured like petals. - Nuri Mass, "Australian Plants', Vol. 7, Dec. '73.

Orchids can be found growing on trees and shrubs and are known as EPIPHYTES or aerial rooted plants, or on rocks when they are termed LITHOPHYTES. Those which grow on the soil are known as TERRESTRIALS while those terrestrials which grow in association with decayed wood are called SAPROPHYTES. Orchids from temperate climates are mostly terrestrial while those from tropical areas are usually epiphytic or lithophytlc.

TERRESTRIAL or GROUND ORCHIDS 'Wherever you live, go out into the bush in spring and summer, to swamps, rock ledges, forest, open woodland. Look carefully around you, close to your feet, among the grasses and low shrubs, on roadside verges and the edges of cultivation; in sunlit clearings and along the borders of bush tracks. Look with special care in areas that have new growth after bushfires. Orchids are found in all these places ..and they are accessible to all of us .. the ground orchids, often overlooked as the poor relatives of the showy tree-dwellers, but often more beautiful in close-up and more interesting." - Densey Clyne, "Australian Ground Orchids'

Terrestrials have a root system of either tubers, e.g. Pterostylis, or rhizomes, e.g. Cryptostylis They generally occur on sandy, loam or clay soils, or in forest humus. Some genera grow on the trunks of tree-ferns, in the forks of trees, or mossy rocks. Saprophytes, e.g. Gastrodia, Dipodium are parasitic on roots, developing a symbiotic relationship with fungi in the soil. It is now generally thought that all orchids have a degree of this inter-relationship, often with a specific type of fungus.

With most terrestrial orchids, the leaves are usually quite narrow or grass-like. The foliage dies back each year and the nourishment from the leaves is diverted to underground storage tubers which swell. Some terrestrials are evergreen, e.g. Phaius sp. while others have no leaves, e.g. Cryptenthemis sp.

The_best known TERRESTRIAL GENERA are:

• Acianthus Insect orchids
• Caladenia Spiders
• Caleana Duck-orchids
• Calochilus Bearded orchids
• Chiloglottis Bird orchids
• Corysanthes Helmet orchids
• Cryptostylis Tongue orchids
• Dipodium Hyacinth orchid
• Diuris Doubletails or Donkey orchids
• Gastrodia Potato orchids
• Glossodia Waxlips
• Lyperanthus The "Beaks"
• Nicrotis Onion orchids
• Orthoceras Horned orchid
• Phaius
• Prasophyllum Leek orchids
• Pterostylis Greenhoods
• Spiranthes Ladies' Tresses
• Thelymitra Sun orchids

Refer to a good reference book for descriptions of these orchids and their habitats. Do not depend on common names even though with orchids they are widely used and often very appropriate. They vary from place to place and can be very misleading.

EPIPHYTIC ORCHIDS represent only about a quarter of Australian orchid species, growing mostly in warmer rainforests in NSW and Queensland. The word epiphyte means "on a plant". Such plants are not parasites but use the tree or rock to lean on for support. They have soft spongy adventitious roots which absorb moisture. They also have pseudo-bulbs or back bulbs for storing food and moisture. Minerals and nitrogen are obtained from the dead outer layers of the bark of the tree or from debris that collects about it. The roots of epiphytes also stabilise the plant as they find their way into the fissures of the tree bark or the rock. As the dead material and bird guano rot in the humid conditions, some of the chemicals dissolve into the water it collects, allowing the orchid to take advantage of its nutrients. There is much more variation in shape, texture and arrangement of the leaves of epiphytic species.

The best known EPIPHYTES and LITHOPHYTES are:

Bulbophyllum - a very large genus found in coastal rainforests from northern Old to the Clyde River, in NSW. The flowers are small but very numerous. It responds well to cultivation.

Cymbidium - the name means "boat-shaped". The three Australian species are fairly large plants growing in hollows of trees. C. madidum is the most reliable in cultivation.

Dendrobium - a very large genus with at least 60 Australian species with quite a number of natural hybrids. Most are epiphytic on trees but a few are lithophytes, notably the Rock orchid, D. speciosum. They are hardy, needing fairly bright light. In nature they are periodic in flowering. In years when they grow well, they do not produce many flowers, and vice versa.

Sarcochilus - a much-cultivated genus with eleven Australian species. S. falcatus, the Orange-blossom orchid, is a shade loving plant which favours soft wood trees in moist gullies.

With this widespread distribution, the diversity of form, the intricate structure and beauty of the bloom, is it any wonder that orchids enjoy such enormous popularity with a vast number of botanists and horticulturalists, both amateur and professional?

GROWING NATIVE ORCHIDS Many people are scared off growing native orchids but there are many enthusiasts achieving success in cultivation and breeding. Obtain a good reference book. You may like to join an orchid group where you will meet other growers willing to share their experiences. There is an Australian Native Orchid Society which would welcome you to meetings in your area.

TERRESTRIAL ORCHIDS are not as commonly grown because of the difficulty of obtaining plants. The National Botanic Gardens in Canberra has built up a collection in containers to study as many species as possible, concentrating on propagating from seed. The soil mix used comprises coarse sand, softwood shavings, leaf mould and basalt loam. Inorganic fertilizers are not used as this mix provides nutrition. All pots are allowed to dry out during the surmner months when the orchids are dormant.

For growing in containers a number of compost recipes is available. The mostimportant factor is good drainage. Squat pots are best. Species with tubers don't like to be surrounded by excess soil mix.

Terrestrial orchids will grow in the garden with limited success but are enjoyed by slugs and snails. you must have a soil compatible with their habitat, lime and salt free and friable.

EPIPHYTIC ORCHIDS are much more commonly cultivated. They can be grown in pots or baskets, preferably shallow ones, using a free-draining compost of bark fiber and charcoal. Other suggested materials are granulated polystyrene foam, peat moss or coconut fibre, inert grit/gravel, leaf mould, rice husks, coarse sand, vermiculite or perlite, sphagnum moss, chopped treefern fronds etc. All orchid growers have their favoured medium. When orchids become overcrowded, repot while they are dormant.

Many epiphytes and lithophytes are grown in a way which resembles their natural fashion, attached to cork boards or tree fern segments rough hardwood blocks or paperbark logs, clay drainage pipes etc. Growers with bush landscapes fix them to trees and logs in sheltered positions. Nylon fishing line is a good twine to use. These orchids like a warm, moist atmosphere, similar to their natural habitat. Some species are much more adaptable than others and experimentation will show you what is possible in your climate. If you are fortunate to have a glass house or bush house make sure air can circulate and there is no fungal- attracting debris.

The degree of light or shade needed varies from species to species. Give orchids a good, deep watering we when they need it. But spare the water while they are dormant. Use a slow release pellet fertilizer formulated for native orchids, blood and bone, very old animal manure. Some growers prefer liquid preparations. Whatever you choose, use sparingly. Don't overfeed.

Pests and Diseases. Watch for aphids, red spider mites and thrips and other nuisances and treat with carbaryl or malathion as is appropriate Use a safe bait for snails and slugs. Prevention is about the only cure for viruses. Keep your tools and benches free from infection and don't propagate from diseased material. Fungal conditions should not be confused with viruses. Use a suitable fungicide to combat mildew, root rot, botrytis.

REMEMBER: Native orchids in the wild are protected. Habitats have been greatly reduced by urban and agricultural development. Many species are threatened or are already extinct. Others have been ruthlessly harvested by collectors. Leave orchids where they arel

Adapted from a leaflet produced by the Society for Growing Australian Plants.

A project of the Blue Mountains Group.