Western Suburbs Orchid Society

Rockdale Plaza, Spring Show. 23rd to 26th October 2008.

Note that the next visit of the Orchid Tray Company will be at The November meeting

Our next meeting will be held on the 22nd September, 2008. Meeting highlight will be Doctor Fred Lomas with a talk titled “I do it this way”.

In Rentoul’s book Growing Orchids Book Two The Cattleyas and other Epiphytes on page 118 there is a picture of Oncidium Savanna Sunset. The caption reads “small is beautiful just as big is beautiful. These flowers are less than 3 centimetres long and originated in the species O triquetrum and O pulchellum, two species occurring in the islands of the Carribbean area of the Central American region. The plants have no pseudo-bulbs, thick and channelled leaves and the whole plant somewhat reminiscent of the aerides of the Asian area. The spikes are long and wiry and the flowers usually sparse. It is developed from warm growing oncidiums and this section, being so different morphologically from the oncidiums, has been suggested as a separation from that genus”.

The trigger for the beginning of my collection was a listing from Aranbeem Orchids and the picture.described above. You can detect the enthusiasm of the list writer in the following.

“MINIATURE ONCIDIUMS Includes a special selection from Robert and Susan Perreira in Hawaii. Established on cork mounts $3.50 each or in 2″ tubes where stated. Due to the vast amount of hybridisation of these little ‘beauties’ it is now impossible to predict with any certainty the anticipated colour of any cross. As those who have seen our own Private Collection have observed - the colour range of any cross is enormous. Most of these should flower within 12 months. They thrive in ‘Hardcane Dendrobium ‘ conditions - plenty of air circulation, regular watering; but must dry within half a day.”

These were the days when I would try to grow anything, so long as it was an orchid, so I purchased ten of the ‘little beauties’ not knowing that they are considered difficult to grow in Sydney. They arrived mounted on little blocks of cork. When most of them flowered within the promised twelve months, I was hooked.

Cultivation Notes

Pots and Mounts: You can grow them mounted on cork, treefern slabs or in small clay or plastic pots. Mine are growing in 50mm plastic pots, which have enlarged drainage holes. Pots are shortened to approx. 50mm depth to further improve drainage.

Potting Mixtures: Suitable materials are pine bark, red scoria (lava rock), small pebbles, polystyrene, small amounts of dried bracken fern, coarse river sand and sphagnum moss. The proportion of these materials depends on your growing conditions. But, as stated above the mixture must dry to just damp within half a day. The tiny roots will die if kept wet. The trick is to provide just enough moisture to keep the plants growing. Use sphagnum moss with discretion, a small amount used on the surface of the potting mix helps in maintaining the desired just moist condition.

The plants can be planted in straight sphagnum moss provided the base of the plant is well above the rim of the pot. Bracken fern is believed to provide beneficial fungi, which assist the roots.

Growing conditions; A covered enclosure is essential, plants grown in the open or under shadecloth slowly decline in the Sydney area. Mine are grown mounted on trellis wire on the south wall of a warm glasshouse. Air movement is provided by a box fan. The south wall provides maximum sunlight in winter, less sun in summer.

My glasshouse has a hail guard of 50% green shadecloth, extra shade is provided in the warmer months by a routine of only cleaning the glass roof in late autumn.

Plants will survive low night temperatures provided you are ensure that they are not wet. Watering frequency will decline to weekly or fortnightly in winter depending on the weather. Plants will survive because roots will absorb water during the night when the humidity rises as the temperature drops. Always water in the morning on a day that promises to be sunny.

General maintenance; Inspect plants for scale, mealy bugs at regular intervals, take prompt action if either appear because these pests are hard to get rid of once established. Remove stumps of dead growths and any associated dead roots. Divide and repot plants in early summer once the major flush of flowers is over in October/November. When dividing plants try to keep at least three growths.

Names; The species have been moved to the genus Tolumina while the hybrids are still recorded as Oncidiums.

Cattleya, to many people this word conjures up steaming jungles, the Amazon, tropical downpours, hothouses and expense. This myth originated from England where only the wealthy could afford the hobby. In fact the myth still exists! It is amazing how many people believe that you need a “hothouse” even in Sydney. Cattleyas do not grow well when subjected to continuous excessive heat. Instead of the Amazon, think of the Atherton Tablelands near Cairns, warm days, cooling breezes and cool nights.

The word Cattleya in these notes refers to Cattleyas and hybrids with other genera. A few of the original species did come from tropical lowlands but many come from cooler regions, such as the slopes of the Andes mountain range. Some come from semi desert areas of Central America.   Cattleyas grow well in the Sydney area, particularly those that flower in the autumn. I suppose you could call them cool cats but this is really a misnomer because you need the warmth of summer to initiate autumn flowering. If you are a beginner, start off your collection with these and graduate to the winter and spring flowering types as you gain more experience.

Major growing requirements are warmth, air movement, correct amounts of shading, adequate amounts of water, a growing medium and a fertilising program.A glasshouse would be nice but is not necessary, start off with a shadehouse or similar, a description of my shadehouse follows as a guide:Frame built of galvanised pipe, approximate dimensions are 3 metres x 5 metres, height 2.5 metres. Orchids sit on wire benches or are hung from pipes across the roof. Shadehouse is covered with green knitted shadecloth rated at 50 per cent shade. The roof has an extra layer of 50 per cent shadecloth which is removed at the end of April each year and put on again at the end of August.

Your shadehouse should be placed in the sunniest possible spot. You can always add an extra layer of shadecloth if necessary, too much shade will result in lush looking growth but few flowers. If you live in the parts of Sydney where frosts are prevalent, extra protection can be provided in winter by a layer of plastic on the roof.

Watering: Watering frequency depends on the weather, time of year, your potting material and the micro climate created in your shadehouse. It can range from daily in the heat of summer to fortnightly in the middle of winter. Always water in the morning so that the plants partially dry out by nightfall. Let the plants dry out so the potting mix is just moist below the surface before watering. If in doubt, do not water, water the floor of the shadehouse to keep the air moist instead. Do not water plants in the middle of the day during a heatwave (you will burn them) just water the floor so that evaporation will cool the air.

Growing Medium: Most growers use treated pine bark, coarse grade for mature plants, finer grades for seedlings. Unless you have a large collection it is best to buy a quality prepared bark, rather than prepare your own, a proven recipe for treating bark is: 

“Peter’s” formula for soaking bark to treat one 50 litre bag

Urea - 130 Grams

Copper Sulphate - 10 Grams

Soak bark in this mixture for 10 days. Treatment provides some nutrients and reduces acidity so that orchid roots are not damaged. 

Some growers add other materials, such as pebbles, polystrene chips, vermiculite, charcoal to lighten the mix. It is a matter of experimentation to get the mix right for your growing conditions. 

Do not use polystrene beads used to fill bean bags because some brands have been treated with a chemical that damages plants. 

Pots and Pot sizes: Use squat plastic pots rather than the taller types because cattleyas grow better in them and you do not have to worry about putting crocks or a layer of polystrene pieces in the bottom. Also, squat pots are more stable. Clay pots are excellent, but expensive and tend to dry out quickly so they are not used much these days. Choose a pot appropriate to the size of the plant, never overpot, because the potting medium will not dry out and the roots will rot. The plant should fit snugly in the pot, new roots should easily reach the sides of the pot in the current growing season. Better to underpot than overpot.  

Fertilisers: The rule is, little and often. Apply at less than the recommended amount in the instructions, half or even a quarter of the amount is appropriate. Some growers apply very dilute fertiliser with every watering. For new growers once a month should be sufficient. 

I like to alternate between organic and inorganic fertilisers, for there is no proof that one is any better than the other. An occasional application of Magnesium Sulphate (Epsom Salts) seems to be beneficial. Two tablespoons in a bucket of water is plenty.  

Labels Explained: A wealth of information appears on the plant Labels. Try to maintain these labels because plants labelled as unknown lose some of their resale value. A typical label would look like this: 

Blc. Memoria Crispin Rosales ‘No 2′ AM/AOS 

Blc. Is the abbreviation for Brassavolo, Laelia, Cattleya which are the genera used in the breeding to produce this hybrid.

Memoria Crispin Rosales Is the grex (family) name used for the seedlings produced by crossing Lc. Bonanza x Blc Normans Bay. Note the use of capitals in the name to denote a hybrid.

‘No 2‘ Is the clonal name for this particular seedling. (A mundane name for a beautiful flower).

AM/AOS Denotes Award of Merit, American Orchid Society.  

Other Cattleya combinations you may see on labels are:

Slc. Similar to above except that Sophronitis appears in the breeding.

Potinara Named after Dr Potin. Species used are Brassovolo, Laelia, Cattleya and Sophronitis.

Rolfeara Species used are Brassovolo, Cattleya, and Sophronitis…… there are at least 60 of these combinations of Cattleya used with other species. 

Species names are written in lower case: Cattleya intermedia, Cattleya aurantiaca, Cattleya bowringiana, Cattleya mossiae etc. Natural varieties are indicated by the abbreviation var. and clonal names are enclosed within single quotes.

Some examples: Cattleya intermedia var. alba , Cattleya loddigesii var. coerulea ‘Blue Sky’  

Natural hybrids, those hybrids which occur in the wild are indicated by an ‘X’ in front of the name.

Example: C. Xhardyana , natural hybrid of C. dowiana x C. warscewiczii. 

Other quality awards are AD, HCC and FCC, respectively, Award of Distinction, High Class Certificate and First Class Certificate. The quality award is always followed by the name of the awarding society, examples are; OSNSW AOC (Australian Orchid Council), QOS (Queensland Orchid Council) and so on. 

Repotting: Plants need to be repotted every two years or when the growing lead is over the edge of the pot. Remove dead pseudobulbs and dead or broken roots. If the plant is large, it can be divided, but try to keep the divisions no smaller than four pseudobulbs and the growing lead. Autumn and Winter flowering types should be repotted in early spring. Repot the Spring flowering types once the flowers are spent. Tidy up and secure the plants with stakes. Make sure that the plant is secure in the pot and place a small amount of sphagnum moss under the growing lead to encourage root growth. Face the repotted plant so that the growing lead gets the morning sun.  

Pests and Diseases: The worst pest is boisduval scale which allowed to go unchecked will result in the loss of growing eyes and general decline of the plant. Minor infestations can be controlled by spraying with a mixture of 50% water and methylated spirit. Major infestations need to be sprayed with commercial mixtures of white oil and malathion. Similar treatment is appropriate for mealy bug. 

Control slugs and snails by scattering snail and slug pellets around your collection. Fungus diseases are kept at bay by good culture. If necessary, seek help from your local nursery for an appropriate remedy. Follow the safety directions when using poisonous chemicals.  

Outside Culture on trees etc.: Suitable hosts are shrubs or trees which do not shed their bark such as frangipani, bottle brush, citrus trees. Cattleyas can also be grown on tree fern slabs or slabs of cork. Tie plants to host with old stockings or similar. Try to find protected spots where the orchids get filtered morning sun and protection from the hot afternoon sun. Do not place plants in situations where they are exposed to full sun, leaves will burn, even in June.  

Other Cultural Information: Cattleyas grow best when there is a daily variation in temperature. A minimum of 12C rising to 26C is much better than a constant temperature of say 20C. This is why it is difficult to grow them in your house. Optimum humidity level is about 60 per cent. Avoid situations such as sun rooms where dry winter air is heated. If you do not have an outdoor growing area you might have some success indoors with an easterly aspect where there some sunshine, a temperature variation and moderate humidity levels. 

Flowering: Plants will only flower from the new pseudobulb. Most autumn flowering plants will commence bud development once the pseudobulb is mature. Some of the winter and spring flowering types need a resting period before bud development is initiated. Some plants will form a single or double flowering sheath, others will form buds directly from the tip of the pseudobulb. Do not despair if the sheath turns brown, the plant may still flower.  

Once the buds are nearly mature do not move the pots, otherwise the stems may twist and the flowers will not be displayed nicely. Once open, the plants should be moved to a protected situation so the blooms are not spoiled by rain or dew. 

Once flowering is complete, the plants should be returned to the growing area, make sure all flowering sheaths are split so that water does not collect there and rot the pseudobulb. 

Maintenance during the year: Every few months go over the collection checking for mealy bugs and scale which may be hidden under leaves or sheaths surrounding the pseudobulb. Tidy up by removing dead leaves, old flower spikes and dead sheaths, restake plants as necessary. Plants which may need dividing in the coming potting season can be backcut to encourage new leads to form.  

Seedlings and mature plants can be potted on anytime up to the end of March, try not to disturb the roots during this process.  

Seedlings and smaller plants need more shade and humidity than mature plants. It may be necessary to relocate some plants in your shadehouse as the seasons change. 

Building your collection: Many beginners start off buying tiny plants because they are inexpensive. The trouble with this approach is that much expertise is required to raise plants to flowering size. Also, some clones need many years of culture before they will flower. A better approach is to start off with mature plants. Some of those for sale may be discards and not of championship winning quality, but gaining experience is more important than flower quality if you are a novice. In building your collection try to get a mixture of seedlings and mericlones (copies) of better quality plants. Also, build your collection so that you have a mixture of exhibition, miniature and compact, bifoliate and cluster types.

This beautiful Stanhopea flowered on Christmas Day, 2007. What a wonderful Christmas present.

Stanhopeas are excellent orchids for novice growers and do well in Sydney’s climate.

The Western Suburbs Orchid Society website is currently having a face lift. Stay tuned for exciting new features.