VandaVanda
The Vanda Genus is one of the most popular group of Orchids grown. Extensive hybridising has been done within the genus and with other genera to produce orchids of exceptional beauty. There are three distinct groups of Vandas which are easily distinguished by the shape of their leaves:-
Strap-leaf Vanda has rather flat, broad leaves growing close together, alternating on the right and left sides to give a beautifully symmetrical plant. The flower stem also alternate sides, coming from the axils of the leaves on the upper part of the plant.
Terete-leaf Vanda
has cylindrical leaves, shaped like and about the thickness of a pencil on mature plants. Their leaves grow to four to six inches long and are sharp or blunt tipped, with their bases encircling the stem. The flower stems appear on the side of the stem opposite the leaf. They are Sun-loving Orchids.Semi-terete Vanda
is a hybrid between the Strap-leaf & Semi-terete Vandas and the leaves are somewhat in between. These orchids require bright light, and upon hardening can be grown in full sun, so are ideal for landscaping in frost free areas. They will reward you with multi-spikes of beautifully coloured blooms several times a year.
V. denisoniana
VANDACEOUS INTERGENERIC HYBRIDS
ASCOCENTRUM
This is a small genus closely resembling Vanda which breeds freely, although not naturally with the latter Genus to produce the ever popular Ascocenda. The Ascocentrum resembles the appearance of a small Strap-leaf Vanda with erect inflorescences of many small brightly coloured flowers facing all directions. The blooms are extremely bright and even in colour. Each flower is flat in form and has a long spur which points vertically downwards. This delightful genus is found growing in the deciduous trees in Northern Thailand, Burma and the Himalayas.
Asctm. ampullaceum
This lovely little species has been line bred to perfection, with the use of superior clones. The sturdy plants stand about 250 cm tall and have leathery leaves about 135 mm long. The multi-flowering spikes appear in the Spring and Summer bearing many flowers of deep rose to rose-magenta. These delightful, easy to cultivate plants appreciate intermediate growing conditions.Asctm. curvifolium.
These plants are easily recognised by their very rigid down curving leaves, on plants which rarely grow taller than 165 mm. These small plants produce multi-spikes of orange-scarlet to cinnabar red blooms in the Spring and early Summer. This rewarding species likes to grow in intermediate to warm growing conditions.Asctm. miniatum
This species is easily cultivated in diverse situations, mainly requiring bright light and intermediate to warm conditions. These miniature plants rarely grow taller than 145 mm and have rigid fleshy leaves with multi-spikes of tightly arranged, bright orange-yellow blooms appearing in Spring.
RHYNCHOSTYLIS
There are three species in this Genus: Rhynchostylis
coelestis, Rhynchostylis gigantea and Rhynchostylis retusa. Much effort has been
directed towards the production of superior forms of these species through
inter-clonal breeding.
Rhy. gigantea
There are three colour forms of this lovely perfumed species. The common variety has white flowers spotted with amethyst purple. There is also the much sought after rich, plum red variety and the pure, crystalline, white form. These plants are seasonal bloomers, usually flowering late Winter to Spring. Rhy. gigantea `Red’ has been used extensively in Intergeneric Hybridization, producing several outstanding hybrids such as Renanstylis Queen Emma, Rhynchovanda Sagarik Wine, Opsistylis Lanna Thai, Opsistylis Suree and one of the latest one being Rhynchovanda Colmarie. This rewarding species will tolerate short spells of cold weather without noticeable stress.Rhy. coelestis
Has a colour range which includes the rare pure white, bright forms of pink to the azure blue. Cultivation; As for Strap-leaf Vandas but will be more tolerant of short spells of cold weather. This species is transfertile with other Vandaceous genera producing upright spikes of richly coloured blooms. Their intergeneric progenies are quite cool tolerant and are known to be easy to cultivate. Vascostylis Precious, Vascostylis Pine Rivers and Vascostylis Fuchs Sapphire are three fine examples which have Rhynchostylis coelestis in their immediate parentage.Rhy. retusa The famous Foxtail Orchid - Beautiful pendulous spikes which are 15 cm in length with 100 - 140 flowers of 2 cm in diameter. The blooms are white with minute amethyst spotting on all segments. The pure white form is of exceptional beauty and is a must for the serious collector of rare species. Line bred varieties of this particular species are proving to be more easily cultivated in captivity than the plants which were originally collected from the mountainous regions of Burma and Thailand.
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AERIDES
Chtra. Renee Gerber = Aer. lawrenceae x Ascda. Bonanza
Chtra. Ruth Murai = Aer. lawrenceae x Ascda. Yip Sum Wah
Aerctm. Fuchs Gem = Aer. lawrenceae x Asctm. miniatum
NEOFINETIA
Neof. falcata
produces multi-flower spikes bearing about six pristine, white flowers which are deliciously fragrant in the evening. These charming little plants prefer to grow on the cool side of intermediate temperatures. Recently there have been many more Intergeneric Hybrids made with Ascocenda and Vascostylis - all are very charming and very easily cultivated plants producing multi-spikes several times a year.
INTRODUCTION
The structure of our orchid house has been dictated by elements like light, air movement, humidity and temperature. I will discuss these effects in more detail under each heading as I progress through this paper but basically our main orchid house is a 60m x 32m shade-house of galvanised pipe construction with a flat roof 2.5m high. We hang our adult strap-leaf Vandaceous orchids with most smaller sizes placed on flat weldmesh benches about 900mm above the gravelled floor. The Eastern & Northern walls are covered with shadecloth and Southern & Western walls are enclosed with clear Alsynite.
LIGHT
Adult strap-leaf Vandaceous orchids require 60 - 65% shade. Out of necessity, Fred & I discovered a great way of providing a combination of warmth and the correct amount of shade to our strap-leaf Vandaceous. About six years ago, we noticed that the plants were starting to burn underneath the 50% black shadecloth we had provided (possibly owing to the depletion of the ozone layer?), so we erected another layer of 30% green shadecloth about one third of a metre below the existing black shadecloth. This has worked perfectly for the adult plants. As the black shadecloth attracts plenty of warmth, the shade-house warms up quickly on a cold winter’s morning. The adult strap-leaf Vandaceous are growing and flowering beautifully, hanging in their baskets & clay pots in the 65% shade. The semi-terete types require a little more light so we hung them directly under the 50% black shadecloth only and close to the northern wall which is also made of 50% black shadecloth. This assists them in receiving optimum sunlight all year round. For small seedlings (the first month after deflasking), they are grown under alsynite, receiving 75% shade. Later they are put out in our main shade-house and continue to receive 75% shade under shadecloth until near flowering size.
The clear alsynite on the Southern & Western walls of our shade-house also assists by providing refractive light through the shade-house
AIR MOVEMENT AND HUMIDITY
The Nose Knows
Yes, you can smell if the atmosphere is correct for growing orchids successfully. The air should be buoyant and moist. You may well ask how to obtain and retain good air movement as well as providing high humidity. Orchids appreciate having moisture around them but not on them. We have found hanging Tillandsia usenoides (Old Man’s Beard) around the baskets & clay pots and letting it drape down with and below the root system of the plant, is very beneficial. The Tillandsia catches the water & fertilizer, keeping moisture close to the plant but not directly on the plant itself. We also grow bromelaids, particularly the urn shaped ones, under the orchid benches and hanging plants. The bromelaids catch the water and this creates extra moisture in the atmosphere, hence maintaining the humidity within the shade-house
.Our Vandaceous orchids receive plenty of fresh air. Carbon Dioxide & Oxygen enter and are released through the stomata in the leaves, and as this exchange or transpiration only occurs in Vandaceous orchids at night, good air movement both day & night is essential. Carbon Dioxide is used by the plant in the process of photosynthesis, in which water & nutrients form sugars, the plant foods. The process of photosynthesis is carried out only in the present of light, displaying the importance of the light factor discussed previously
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TEMPERATURE
The majority of Vandaceous orchids thrive when the temperature fluctuates between 10 dgs.C. night time minimum in the winter, and 35 dgs.C. day time maximum in the summer. Vandaceous orchids can however tolerate much greater extremes, falling way below these minimums for short periods. We have experienced a series of winter mornings where temperatures have been down to 1 dg.C and climbed quickly to 22 dgs.C. during the day with no signs of stress shown by the plants, however we do keep them on the dry side when this happens
Vandaceous orchids are very intolerant of long hot periods, when temperatures can rise above 35 dgs. mark. This is when it is very important to keep the humidity up to your plants, perhaps by watering the `Old Man’s Beard’ which you have draped around the root system, and wetting the pathways etc. By doing this you will lower the temperature in the shade-house as well as creating extra humidity.
As mentioned earlier, the Southern & Western walls of our shade-house is covered with clear alsynite not only for light purposes but also to protect our plants against the cold drying south-westerly winds so common during the winter months (especially August.
WATER
Vandaceous plants depend heavily on good quality water. As they have a monopodial growth habit, the plants can not retain water for any great length of time. It is advisable at all times to water these plants as early in the morning as possible, so that by noon the foliage of the plants will be dry. Water left on the plant in the middle of the day, acts like a magnifying glass and intensifies the rays of the sun, causing plant burn. This can be a serious problem if it occurs in the crown of your plant. Orchids do not appreciate being wet and cold, so water your plants in the winter time only on bright and clear mornings as necessary. Adult plants are watered once a week in the winter time and every day during summer.
Young Seedlings in community pots & 50mm tubes are grown under alsynite and are watered every day when the weather is warm to hot, and once a week in the depth of winter, as early as possible in the morning. Always treat your baby plants as you would treat your children and put them to bed dry.
FERTILIZER
Vandaceous orchids are very hungry plants. I always advocate that they are good people plants, as the better parenting they get (feed and care), the better they perform. Our plants are fertilized as early as possible in the morning.
During the growing period:
In general this would be from the beginning of September to the end of March. The Adult Plants are fed once a week as follows: For two weeks we use a well balanced fertilizer and the following week we use a low nitrogen fertilizer. The Young Seedlings are fed once a week as follows: For three weeks we use a well balanced fertilizer and the following week using a low nitrogen fertilizer.During the dormant period:
When the weather starts getting cooler and the daylight hours shorten, we reduce the food to our plants. Adult plants are fed only once a fortnight with a low nitrogen fertilizer in order to keep the velamen on the root system plump. The Young Seedlings are fed only once a fortnight, rotating a balanced fertilizer with a low nitrogen fertilizer. The fertilizers which we use and recommend are:-Peter’s Orchid Special 18N - 7.8 P - 14.9 K
Peter’s Blossom Booster 10 N - 13.1 P - 16.6
Our plants are always fertilized manually, not through the overhead watering system, as we like to observe our plants and concentrate the fertilizer on the root system of the plants, because this is where the plant absorbs most of its nourishment.
In our experience of cultivating these wonderful orchids, this fertilizing program promotes strong healthy new growths which are not prone to disease.
POTTING MEDIA
We pot our freshly deflasked seedlings into a fine mix of 70% and 30% polystyrene in community pots, and the larger plants (from flask) are potted directly into 50mm tubes using the same mix. When the plants have outgrown their 50mm tubes, they are either potted on into 115mm Black Plastic Baskets or 115mm Clay Pots which have extra holes in the sides.
The mix used in 115mm pots is 70% good quality treated bark and 30% larger chunks of polystyrene. In the baskets or clay pots, I put in extra coarse bark and polystyrene to support the plants until the roots have gripped the container, then it is a good idea to tip out the
surplus potting media as it is no longer required. This assists Vandaceous orchids by providing plenty of good air circulation around the root system. They do not like to have wet feet especially during prolonged rainy weather when they can get bacterial rot, particularly if the weather turns cold also.When you tip out the surplus potting mix, it is a good time to put the Tillandsia usenoides loosely around the top of the basket or clay pot and exposed root system.
PESTS AND DISEASES
Observation is the key word. Observe your plants when watering and fertilizing. This is one reason why we fertilize by hand. Keep a sharp eye out for any abnormalities in appearance or performance in your plants. Isolate these plants when located, identify the problem and then deal with it immediately
Fungus and bacterial diseases are usually noticed as a collapse of the plant’s tissues, frequently with a water soaked appearance. You can usually recognise bacterial infection by its offensive smell. Depending on the disease, it may attack the leaves, the stem or the root system.. These diseases require high humidity to survive. Some appear with high humidity and low temperatures, while other types are not activated until the temperatures are relatively high. Discourage these diseases by watering your orchids as early as possible in the morning so when the temperature reaches its peak, your plants will be dry and will remain so as the temperature falls at night. Should any plant show signs of these diseases, isolate it and cut out the diseased tissues with sterilized tools. Paint the cut surfaces with a fungicide such as Dithane. Let the plant dry out for a day or two before returning it to your collection.
Fungal and bacterial problems can be kept to a minimum with good house keeping, no debris left under benches, good air circulation around your plants, and regular spraying with a preventative fungicide to protect your plants against infection.
Mancozeb or Dithane is also used periodically if the need arises, for instance after prolonged rainy weather. Before the onset of Winter, beginning of May, a mixture of Mancozeb and Spraytech Oil is sprayed on the plants, 4 dessertspoons to five litres of water, then mix in a capful of Spraytech Oil. Use a pump spray making sure that a good coverage is obtained to all areas on the leaves. Two days later spray with Envy to protect your plants from cold damage and dehydration. Repeat both these applications mid-July and then at the end of August. Fosjct, active ingredient is Phosphoric Acid, is used to protect your plants against root damage when transporting plants. Infection such as bacteria can enter your plants through injury to the root system then the plant is susceptible to Fusarium Wilt. The first sign that a Vandaceous plant is infected with Fusarium Wilt is that they start to drop the lower leaves. The only remedy to Fusarium Wilt is to catch it early; cut the plant out of the basket then cut below at least three healty roots making sure that the cut is clean and the stem is a nice healthy green colour without any brown marks. Make a paste of Mancozeb or Dithane and paint the cut, lay the plant on its side for a couple of days to dry properly and pot it up. Fosjet may be marketed under a different trade name, ask for product with the main active ingredient being Phosphoric Acid.
Vandaceous orchids are not usually prone to attacks from pests and insects. Occasionally scale or cockroaches may attack, causing a widespread infection in the shade-house. If the need arises, spray with a mixture of Diazinon and White Oil for scale or Diazinon by itself for cockroaches. If you can deter ants from entering your shade-house, your problems with all types of scale, including mealy-bug will be few,
as these insects rely on ants to carry them.
SOME GENERAL TIPS TO REMEMBER
The best fertilizing programme in the world will not compensate for poor growing conditions. When Vandaceous Orchids are poorly grown or carelessly handled, they will fall victim to insects or disease, however with reasonable attention given to their basic needs, their troubles will be few.
The most common question I have been asked is `How do I know which Hybrids or Intergeneric Hybrids grow cool or warm?’ My advice to this question is:- Be guided by the species which appears most frequently in the parental background of the hybrid which you have in mind. A knowledge of the cultivation and habitat of the species is invaluable. For instance, the more that V. coerulea appears on both sides of the immediate parentage of the hybrid, the more cool tolerant it will be. The more V. sanderana appears in the background of the immediate parentage of your plant, the more warm loving your hybrid plant will be.
