Selected Species - by Peter Taylor
PERHAPS the most spectacular, recent discovery in the orchid world is the remarkable Phragmipedium kovachii from Peru. This plant with its massive red flowers has, with Phragmipedium besseae found in 1981 in Peru and Ecuador, rekindled an interest in the genus.
At the recent Australian Orchid Conference a superb display of Phragmipedium hybrids and species, courtesy of Clive Hayman and Rita Cusack (to my eye the finest plants of the conference) initiated much interest and discussion. The elegance of these fine plants certainly caught one's attention and many people went in search of a 'Phrag' or two in the sales area. If lucky they were able to purchase a flask of Phragmipedium kovachii or one of its crossings from Manolo Arias of Peruflora.
The selected species for this month, Phragmipedium caudatum, is the type species of the genus, relatively easy to grow and flower and a good choice for anyone wanting to 'try their hand' in growing phragmipediums.
The name 'Phragmipedium' derives from the Greek 'phragma' (a division) and 'pedion' (slipper) in reference to the divisions of the ovary of flowers and the slipper shaped labellum. There are approximately twenty species in the genus which has a wide distribution from southern Mexico to Brazil.
Left: Phragmipedium caudatum'Green Giant' photo R Taylor
The genus was established in 1896 by Robert Rolfe in the Orchid Review when he placed all South American slipper orchids in the two genera, Phragmipedium and Selenipedium.
Phragmipedium caudatum was originally described as Cypripedium caudatum by Lindley in 1840. It is a robust plant with five to seven leathery, bright green leaves per growth. It is distributed from southern Mexico to Peru and plants grow on forest trees and also terrestrially in shady situations and occasionally as a lithophyte on cliff faces. All plants prefer water seepage areas and this fact is a valuable clue to culture.
If we allow that orchid flowers have the shape, colour and smell they possess solely to attract a pollinator, then the flowers of Phragmipedium caudatum area wonderful example of natural evolutionary engineering.
Flowers are very large with pale green an pink colour tones. The petals are extraordinary. They are ribbon-like and very long; about 8cm when the flowers first open and they grow about 4cm a day for about a week. They can grow to 35cm. The accompanying photograph (an old slid I've had since 1980) clearly shows the petal length. I am unsure of the truth of the old story that petals of this species continue to grow until they touch something. Why such long petals? Surely it is linked to the insect pollinator as I do not believe that flowers have form without purpose.
The culture of phragmipediums in general and Phragmipedium caudatum specifically is usually linked to the plant's need to have constant moisture in the pots and excellent air circulation and humidity (about 70%). Growers have experimented with growing media in their search for a perfect free draining, yet moisture retentive 'mix'. I have found that in my environmental conditions (mid-North coast of NSW, about 1 km from the ocean, mild and humid) sphagnum moss is best for small plants out of flask and seedlings. For large plants I have recently used coir pieces, a mixture of small and medium bark and large perlite pieces This 'mix' with a very small amount of Nutracote granular fertiliser seems to be working well. I grow in an open shadehouse with two layers of 50% cloth in summer, one layer of 50% in winter plus a plastic cover over the shadehouse. I water heavily twice to three times a week in summer and about every ten days in winter.
Some growers place their pots in a saucer of water. I have had no success with this method of culture. The finest grower of paphiopedilums and phragmipediums that I know of, Mal Myers of Taree, grows his phragmipedium plants in a free-draining small bark medium - however the pots are placed in a larger pot which has about 3-5cm of sphagnum moss at the bottom. Mal maintains that the constantly moist sphagnum moss draws the roots toward it without the mix becoming too waterlogged. It certainly works for him!
Phragmipedium caudatum is an intermediate grower and benefits from a reduction in heavy watering and fertilising in winter. I vary the fertiliser used from organic to inorganic, but always feed at about one quarter strength solution.
A word of warning! Do not over-pot phragmipediums. Pot size should always match root development, not leaf size. Smaller pots allow for increased watering and phragmipediums love regular watering in a well-drained mix, rather than sitting in a 'boggy', sodden mix.
There are some wonderful Phragmipedium species to look out for. Apart from the previously mentioned Phrag. kovachii and Phrag. besseae, you might like to try the delicate pink and white Phrag. schlimii, the lovely green Phrag. pearcei or the amazing peloric Phrag. lindenii.
For those interested in Phragmipedium hybrids there are some terrific breeding programmes in operation. Look out for 'Jason Fisher', 'China Dragon', 'Noirmont' and 'Living Fire' as plants with the highest potential. To my knowledge the premium phragmipedium breeder in Australia is Doug Matters in Queensland.
Phragmipediums are relatively easy to grow and offer spectacular, long-lived flowers. I urge you to try a few as they are an asset to any orchid collection.
Peter Taylor Port Macquarie, NSW
© Peter Taylor and Australian Orchid Council Inc 2007
Originally published in "Orchids Australia" April 2007.