Orchid grower's companion Cultivation, propagation, and varieties

David P. Banks

Book - 2005

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2nd Floor 635.9344/Banks Checked In
Portland, Or. : Timber Press 2005, c2004.
Main Author
David P. Banks (-)
Physical Description
224 p. : col. ill
Includes bibliographical references and index.
Contents unavailable.
Review by Booklist Review

Banks assures gardeners that most orchids are easy to grow as long as their housing, temperature, and moisture needs are met. There are more than 30,000 species and more than 100,000 hybrid strains. Bank's companion presents 400 color illustrations, and contains chapters on plant structures, pollination, orchid names, the history of the plant's cultivation, and its geography and conservation. Chapters on the flowers' care offer advice on growing orchids indoors, in the garden, in pots and baskets, and on mounts. Temperature requirements, watering, fertilizing, pests and diseases, and propagation are all discussed. A 126-page orchid directory lists 400 species, hybrids, and variants, and explains in detail their natural habitat and how to grow them. Banks' wealth of practical advice should help and encourage gardeners to grow these delicate flowers. --George Cohen Copyright 2005 Booklist

From Booklist, Copyright (c) American Library Association. Used with permission.

Orchids are threatened in the wild by two main factors -- habitat destruction and overexploitation. However, these factors do not affect all orchids equally. Many orchids hold a precarious existence, with the majority only occurring in geographically restricted areas. This aspect of their biology is their downfall. When the forests are cleared the orchids become extinct. An example of this is Epidendrum ilense from Ecuador. Soon after the species was discovered, the forest was cleared and it is now extinct in the wild. Habitat destruction can come in many forms from clearance of forest for agriculture, mining, logging, or urban expansion to the insidious invasion of non-native species that out-compete the local orchid. It can also be on widely different scales, from the felling of a single tree containing hundreds of epiphytes, or from chemical contamination of a local orchid population, to the clearance of huge tracts of forest for timber. Unfortunately habitat destruction is at its greatest in the tropics where the diversity of orchid populations is at its highest. Habitat destruction does not discriminate between a flamboyant Cattleya or a tiny Pleurothallis . It is indiscriminate, and because of this, habitat conservation is the single most important aspect of orchid preservation. Tropical orchids do not generally die of old age, they are often as long-lived as the substrate they grow on, and therefore it is only when this is destroyed that the orchid dies. This may allow some orchids to survive habitat destruction until a time when the forest can regenerate. It is not the highly showy orchids that are threatened with extinction, as most of these are already entrenched in cultivation. Rather it is the many miniature species, with little horticultural merit, such as Pleurothallis and the related Stelis from South America that are under threat. In reality, only a small percentage of the world's orchid flora is in cultivation in specialist nurseries, botanical institutions, and private collections. Orchids form a part of a very delicate and complex ecosystem that can easily become unbalanced. Most orchids have evolved to attract a specific pollinator. If the pollinator disappears the orchid may die out over a period of decades (or perhaps earlier). Despite this, new species continue to be discovered, and a number of "lost" species have been relocated. Ironically, as more and more forests are cleared, people have been able to gain access to areas that were previously inaccessible or required many days' hiking over difficult terrain. A number of rare and unusual species of orchids and other ornamental plants are still being found in countries such as Ecuador and Colombia in South America, and Sumatra, Sarawak, and Sulawesi in Southeast Asia, as well as the highlands of New Guinea. Yet, one wonders how many species have become extinct before they have ever been recorded? It has been estimated that a plant species is lost everyday -- obviously, a large percentage of these would be orchids. While most epiphytic orchids are amenable to cultivation, saprophytic orchids and some terrestrial species are almost impossible to grow using traditional methods, and relocation of plants is rarely successful. Their only chance for survival is preservation of their habitat, hopefully under national park protection. Overcollection of orchids from the wild generally only affects a small number of horticulturally important genera, such as Paphiopedilum and Phalaenopsis . Orchid populations are often small, therefore collecting can have a serious effect on the survival of the species and in certain cases has led to the extinction of the species in the wild. Recently a number of exciting new species of Paphiopedilum have been discovered in Vietnam. One in particular, P. vietnamense , caused a sensation. Large numbers of this species came onto the market illegally, leading to their extinction in the wild less than five years after being discovered. However, it is not just the new rarities that are under pressure. Species that are relatively common in cultivation are also under threat. One case is Phalaenopsis violacea . A nursery stripped whole populations of this species from the wild to try to find an unusual white-flowered form. When they flowered in the nursery, the white-flowered individuals were selected and the remainder discarded. Community attitude has certainly changed over the past few decades. Over a century ago, countless thousands of orchids were stripped from the forests to satisfy the greed of many of the Victorian orchidists of the day.This action didn't cause any alarm as there was always "plenty more where they came from." As recently as the 1970s there were still nurseries advertising in orchid periodicals that they could supply orchid species in "lots of up to 10,000." In the same decade, an American journal featured the rediscovery of the rare mustard yellow Paphiopedilum druryi from southern India. Yet, in the same issue, an advertisement appeared offering the plants at inflated prices. The advertiser had collected every plant he could find in a tiny habitat that was about the size of a ballpark. All orchids have been placed on Appendix II of CITES (Convention in Trade on Endangered Species of Fauna and Flora), with species such as Papliiopedilum on Appendix I. This international body restricts the trade between member countries of endangered species. Under CITES legislation, the trade in "Appendix I" plants, such as Paphiopedilum , was banned. No "wild" plants were to be collected and subsequently exported from the native rainforests. Strict documentation, from both the importing and exporting countries, has to be in place before plants can be transported between countries. Failure to comply can lead to total shipments being confiscated. The slipper orchids will probably never become extinct because they are entrenched in cultivation in orchid houses throughout the world, from botanical gardens, to nurserymen, to backyard hobbyists and home gardeners. In many ways, they have become highly successful. The well-documented example of Paphiopedilum delenatii is such an orchid. Only two or three plants of this delightful pale pink-flowered Vietnamese species entered a French nurseryman's collection in the 1920s. They were pollinated when in bloom and the seed subsequently sown, with increasing numbers of young seedlings being produced year after year. This went on for decades, and the species has since become entrenched in cultivation around the world. Admittedly, there was little variation between these plants as there was minimal genetic diversity. This was one of the great achievements and success stories for orchid conservationists, until fresh populations were rediscovered in the early 1990s and thousands of plants were ripped out of the forests to such an extent that it is now thought to be extinct in the wild. However, it does illustrate what can be done if the plants are put into the hands of competent nurseries. The stunning fire engine red Phragmipedium besseae was discovered in 1981, and it immediately shot to the top of the "want list." Initially wild-collected plants fetched several hundred U.S. dollars each, whereas nursery-raised plants, of selected higher quality than the original random wild plants, now sell for a fraction of this amount. It is again thanks to professional nurseries, such as the Orchid Zone in California, USA, that vast numbers of rare species are being reproduced. There are now many more plants of Phragmipedium besseae around the world than existed in the wild before 1981. Even so, this does not help the species in the wild, since it is now very rare in Peru and Ecuador. Botanical gardens also have an important role to play. They ensure that rarities are propagated and made available to the wider orchid community. Without them some novelty orchids, such as Epidendrum ilense and Pleurothallis viduata , may have become extinct. They were originally discovered in Ecuador, South America, on fallen timber that was about to be burned. But unfortunately, since then, they have never been relocated in the wild. All such plants in cultivation, which now number in the hundreds or possibly thousands, have been derived from only one plant of each species. Clearly growers will always want new species as they are discovered, as well as the rarities, and why not? However, this should not be to the detriment of species in the wild. Systems need to be put in place so that orchids can be rapidly propagated, which would require the building of large-capacity greenhouses in the underdeveloped countries where orchids are often found. The species at real risk are the countless miniature orchids, which were often used as packing for more valuable orchids. These have little commercial value and are only of interest to botanists and species enthusiasts. Excerpted from Orchid Grower's Companion: Cultivation, Propagation, and Varieties by David Banks All rights reserved by the original copyright owners. Excerpts are provided for display purposes only and may not be reproduced, reprinted or distributed without the written permission of the publisher.