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Conservation through Cultivation

by Andrew Cartwright

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Photo: Brahea aculeata in Sinaloa, Mexico

I sometimes despair about the destruction of our Earth's beauty. Every year many different kinds of animals and plants become extinct. They will never be seen again. For many years I felt that all I could do to remedy this awful situation was to support the work of organizations concerned with conservation; but recently, I have begun to think that I may be able to play a more direct role in conservation.

Out of a total of about 2,750 species of palm, nearly a third are threatened with extinction in the wild (source: "1997 IUCN Red List of Threatened Plants" compiled by the World Conservation Monitoring Centre). Conservation of palms in the wild is largely dependent upon protection of the habitats in which most of these palms live. Despite the magnificent efforts of several organizations, such as Greenpeace, who are working hard to protect these habitats, the scale of the problem appears to be so large that it seems unlikely that these projects alone will be sufficient to prevent many species of palm from disappearing.

A few of the threatened species are well established in cultivation, and, although cultivation is not an ideal substitute for preserving a species in the wild, it is surely better than losing the species entirely. Unfortunately, many of those species threatened with extinction in the wild are rare, or even non-existent, in cultivation.

Whilst this is a gloomy picture, there does seem to be a precaution that we can take, rather like taking out an insurance policy. My reason for writing is to ask the membership what they think of my proposal. It is possible to purchase plants or seeds of some of those palms that are both threatened with extinction in the wild and rare in cultivation. My hope is that by raising and caring for some of these, we, as amateur growers, may be able to help preserve them for future generations. Our action may not help to safeguard them from destruction in the wild, but, providing we buy from reputable sources, neither will we hasten their destruction.

Although conservation by amateur growers may not seem to be an ideal approach to the problem of saving palms from extinction, it does seem to be a way in which some species, which will probably become extinct in the wild, might be saved for future generations. Certainly, if a species is destroyed in the wild, every plant of that species which survives in the collections of amateurs will become more precious.

Unfortunately, the fact that a species is kept in botanical gardens is not sufficient to guarantee its survival. Genetic variety is important for the survival of a species because plants that are genetically identical are likely to be vulnerable to the same pests and diseases. It seems that variety is more likely to be maintained if the species is kept not only in botanical gardens but also in numerous small populations belonging to amateur growers. Also, there is a possibility that a species may become extinct and then, at a later date, an attempt may be made to reintroduce it into the wild. Successful reintroduction seems more likely if greater numbers of the species are available, and, once again, small populations kept by amateur growers may prove invaluable.

I do not know of an example of a palm that has been reintroduced to the wild; instead, I would like to refer readers to an article about a bird. See Tony Juniper's "Plan to bring Spix's macaw back from the brink" in BBC Wildlife magazine, October 2000. In 1990 there were only twelve Spix's macaws left - one in the wild and eleven in captivity. Since then a concerted effort has been made to conserve this species and a number have been bred. The first tentative steps have been taken to introduce captive birds into the wild, where, amazingly, the single bird remaining in 1990 has survived. The project has not yet succeeded, and may never do so, but it does illustrate the possible importance that palms kept in cultivation might have if their species becomes extinct, or nearly so, in the wild.

Conservation is a considerable challenge for an amateur grower. Pessimists quote a long list of problems facing the amateur grower, but I think it is wrong to allow pessimists to discourage us. Whilst it is true that an amateur grower will experience many problems, this is true of any worthwhile project, whether it be concerned with conservation of palms or anything else. Of course, the possibility of solving problems is an attraction for anyone with a positive outlook.

If, as enthusiasts, we can make a success of creating numerous small populations of threatened palms, then we might be able to encourage the wider public to participate. Every year, millions of people buy plants for their home or garden, including a few species of palms of which thousands are bought every year. Many gardeners raise plants from seed, though rarely palms. Most of this vast expenditure goes towards plants that are not threatened with extinction. If just a small amount of this expenditure could be diverted into caring for threatened palms, then this would further increase the chances of those species surviving. Of course, the principle could be extended to other types of plants, and for some suggestions as to which species might be suitable I refer the reader to "Trees in trouble: a new campaign to save world's rarest species," a sixteen page booklet issued free with the above mentioned magazine.

If the members think my proposal is worth pursuing, then I would be willing to devote some of my time to compiling a database of amateur growers and the threatened species of palm which they hold, and which they would one day be willing to donate to a conservation program should the need arise.

For myself, when I buy palms in the future, I will be buying those threatened species that I believe I can successfully look after, and for which I can provide the conditions required by the species for reproduction. Although I am no expert I have drawn up a list of a few palms which seem suitable for cultivation in a cool temperate climate such as our own, or for cultivation indoors, and I would be very interested to have members' comments on the list. I have examples of two: a Chamaedorea glaucifolia, nearly 5ft tall, growing slowly but surely in my living room at a temperature of 70-80°F (21-27°C) and humidity of 65-75%. Excepting for midwinter, this plant grows all year round. I also have a newly germinated seedling of Dypsis decipiens.

Brahea aculeata (Aculeata palm, Sinaloa Hesper Palm): B. aculeata will grow in a sheltered garden in a cool temperate climate. It needs full sun and well-drained soil. It is also suitable for use indoors in a brightly-lit position. Single plants are capable of producing fertile seeds. Height: 5m (15ft) Width: 2.5m (8ft). Conservation status: vulnerable.

Brahea decumbens (Sierra Madre Palm): The leaves of B. decumbens are amongst the bluest found on any palm. It has a decumbent (underground) trunk and is slow growing. Its natural habitat is on exposed hills (in Mexico) so it may be suited to a cool temperate climate although this has not been proven. Indoors, it requires full sun, well-drained soil, and it may benefit from the addition of lime to the soil. Single plants are capable of producing fertile seeds. Height: 3m (10ft) Width: 2.5m (8ft). Conservation status: vulnerable.

Chamaedorea glaucifolia (Glaucous Parlour Palm): This species has a tall and narrow profile (trunk less than 3cm thick) and up to 40 leaflets on each leaf. It may grow to 5m but plants in cultivation are usually less tall. Requires shade and warm subtropical conditions to grow quickly, but will grow slowly indoors in less favourable conditions. Male and female plants are required for fertile seed production. Height: 5m (16ft) Width: 1.5m (4ft). Conservation status: endangered.

Chamaedorea hooperiana: This is a vigorous, clumping species and a native of Mexico. It requires shady conditions and moderate humidity, and is not suitable for outdoors. Male and female plants are required for fertile seed production. Height: 2m (6ft) Width: 1.5m (4ft). Conservation status: vulnerable.

Chamaedorea klotschiana: This is a small, compact, decorative plant from Mexico, with a slender trunk and a small, extended crown of arching leaves. It requires shade, and is not suitable for outdoors. Male and female plants are required for fertile seed production. Height: 2m (6ft) Width: 1.5m (4ft). Conservation status: rare.

Chamaedorea microspadix (Bamboo Palm): This clumping palm from Mexico is suitable for a sheltered garden, in a cool temperate climate, where a well-established plant will take a few degrees of frost. Requires shade and rich, well-drained soil, and tropical conditions to grow quickly. Male and female plants are required for fertile seed production. Height: 3m (10ft) Width: 1.5m (4ft). Conservation status: vulnerable.

Chamaedorea pumila (Pumila Palm): This dwarf species from Costa Rica has leaves that are leathery, dark grey-green, iridescent, and may be slightly mottled. It requires shade and is not suitable for outdoors. Male and female plants are required for fertile seed production. Height: 2m (6ft) Width: 1.5m (4ft). Conservation status: endangered.

Chamaedorea radicalis (Hardy Parlour Palm): This species from Mexico has tough, dark green, leathery leaves, and grows to a height of 3m. It prefers a shady location in a sheltered garden, and may flower when young. This is the hardiest of the genus and mature plants may withstand temperatures as low as -8C. Male and female plants are required for fertile seed production. Height: 3m (9ft) Width: 2m (6ft). Conservation status: vulnerable.

Dypsis decipiens (Manambe Palm): D.decipiens has stiff, upright, leathery leaflets, and is from Madagascar. The stems are yellow. It needs bright, indirect light when young. When mature it may be grown in a sheltered, sunny garden where it will withstand some frost. Single plants are capable of producing fertile seed. Height: 6m (20ft) Width: 2.5m (8ft). Conservation status: endangered.

Dypsis utilis (Vonitra Palm): This is an unusual palm with new leaves that are red and a forking trunk. It requires bright, indirect light, and is from Madagascar. It is not suitable for outdoors. Single plants are capable of producing fertile seed. Height: 6m (20ft) Width: 2.5m (8ft). Conservation status: vulnerable.

Phoenix rupicola (Cliff Date Palm): This palm is native to India where it grows in rocky situations in the foothills of the Himalayas. It has glossy leaflets held in a flat plane. When young, it requires bright, indirect light; but when older, it will take full sun and may tolerate a few degrees of frost in a sheltered garden, although this is uncertain. Male and female plants are required for fertile seed production. Height: 7.5m (25ft) Width: 2.5m (8ft). Conservation status: vulnerable.

Phoenix theophrastii (Cretan Date Palm): The Cretan date palm is one of only two species of palm that grow naturally in Europe. It survives in only a few areas of Crete, Greece, and Turkey, where it grows on rocky slopes in semi arid areas. It has silver-grey foliage and a spiky appearance. In a sheltered spot in a sunny garden, mature plants will tolerate both frost and drought. Indoors the plant requires bright, indirect light. Male and female plants are required for fertile seed production. Height: 6m (20ft) Width: 2m (6ft). Conservation status: vulnerable.

Rhopalostylis baueri (Kermadec Island Nikau Palm): When mature this palm has a swollen crown-shaft, upright leaves, and broad leaflets, thereby giving the appearance of a shuttlecock. When young it can be kept indoors. When older it can be kept in a very sheltered garden where it will require rich soil. It requires protection if the temperature drops below the freezing point. Single plants are capable of producing fertile seed. Height: 7.5m (25ft) Width: 3m (9ft). Conservation status: rare.

Rhopalostylis sapida (Nikau Palm, Feather Duster Palm): R.sapida comes from New Zealand and the Chatham Islands, and is the most southerly naturally occurring palm. It grows in wet forests, often in poorly lit situations. Plants need shady, moist conditions and protection from sunlight until they are about five years old. When larger, R.sapida is suitable for cultivation outdoors in a cool temperate climate. It is best suited to a cool and moist position in a sheltered garden where it will require protection if the temperature drops below about 3°C. Single plants are capable of producing fertile seed. Height: 7.5m (25ft) Width: 3m (9ft). Conservation status: indeterminate.

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