Parramatta and District Orchid Society
By Keith Ryan
Because of increased member interest in these wonderful orchids I have decided to write a few notes on my cultural methods. Softcane dendrobiums are quite easy to grow if a few basic needs are given.
These plants have a definite growing and rest cycle with the growing period starting after flowering finishes in the spring, usually around the beginning of November, and continuing right through to
the early autumn when the canes (pseudobulbs) mature and the terminal leaf is produced. Softcane dendrobiums have their origins in Asia and most of the hybrids in cultivation today have been derived
from the variable species Dendrobium nobile.
Watering at this time should be at least daily and on extremely hot days sometimes watering at dusk can be a very welcome cooling down. It is almost impossible to over water these plants in the growing cycle!
Now the rest period that I observe is from early to mid April right through till flowering finishes around October and at this time fertilizer is stopped completely. It has been said that water should be withheld
completely during the winter months. I find that I must water at least once a week to keep the compost just moist. As the plants are grown under 30% shade cloth all year round I have no control over rain watering
the plants. When the nodes on the older canes start to swell they should be staked to the front of the plant for flower presentation in the spring, and as the flowers start to open this will add greatly to the
weight of the cane hence the need for staking.
A number of important points to the successful culture of Softcane Dendrobiums are listed below.
1.-- After flowering is finished no fertilizer is to be applied until the new growth has grown to about 50 to 70 mm long.
2.-- Fertilizer can then be started using full strength concentration and carried out right through the summer months finishing in April.
3.-- A so-called low nitrogen fertilizer is used such as Campbells Yellow or Peters Hi K as this helps the plants to grow in a more
compact fashion and resulting in better flowering. If nitrogen fertilizer is used taller canes will result in poorer and fewer flowers.
4.-- Keikis (young new plantlets) will sometimes grow in place of flowers and there are a number of causes for this, the main one
is anything that disturbs the root system such as root rot, repotting etc. will result in the plant growing keikis and these will
quickly grow roots to replace the lost root system. This is the plants mechanism for survival and these should not be removed
until the plant re-establishes itself with a root system that can support it.
5.-- If fertilizer is applied during the rest period the plant will grow keikis that will not grow roots as the nutrients
coming from the fertilizer will be enough to sustain them. These keikis will eventually grow roots and after about
12-18 months can then be removed from the plant and potted up.
6.-- Another cause of plants growing keikis is too much shade, these plants can take full sunlight and do better if grown
in strong light. I have heard of one grower that hangs his softcanes on the rotary clothes line in winter for extra light
but takes them in as the sun goes down.
7.-- Compost in the past has been medium treated bark and rice hulls with some styrene foam. I am now trialling some plants
in coconut fibre and bark with the addition of some styrenefoam. However I believe that softcane dendrobiums will grow in
anything as long as it is free draining.
So that's all there is to growing successful Softcane Dendrobiums. All orchids require a balance of water, humidity, light
and fertilizer for optimum growth.
| Den. Felicity Fortescue 'Pink Lady'
|| Den. Sailor Boy 'Pinky'
|| Den. Small Dowan
|| Den. Miyuki 'Louanne'
are what most people first think of as orchids. This genus is easy to grow and very popular in cooler, temperate climates of New South Wales and the southern states.
SHADE is necessary from hot sun. A shade or bush house covered with 50% shade is ideal. Alternatively, dappled shade from a tree or other plants will suffice. Cymbidiums need plenty of filtered sun to flower well. These orchids will grow well, but rarely flower in full shade.
TEMPERATURE. Happy to grow in a wide range of temperatures, cymbidiums will tolerate light frost as long as buds are protected. At the other end of the scale, very hot days are tolerated but plants will benefit from a substantial overnight drop in temperature.
WATERING. Cymbidiums like to stay damp but not wet. To achieve this plants may need to be watered daily during hot, dry weather. Watering in the late afternoon/ evening will also help chill the plants. In winter, watering weekly should suffice.
COMPOST needs to be well aerated and free draining, but still remain damp for a reasonable period. Most cymbidium compost available from specialist nurseries is ideal, beware of generic brands from supermarkets. These are often of inferior quality. A satisfactory mix would be- 4 parts composted pine bark, 1 part Rice Hulls, 1 part coarse river sand or styrene plus lime plus fertiliser to suit.
REPOTTING. Cymbidiums are best repotted during the cooler months, or if they are flowering, as soon as possible after flowering. To avoid stress to the plants, do not repot during summer. If dividing plants, make sure at least 3 or 4 bulbs are left together. Never reuse compost, and sterilise tools and preused pots with bleach or a sugar soap concentrate. After dividing, place plants in a shady area for a few weeks and water sparingly.
FERTILIZER. Most water-soluble fertilisers are satisfactory or a quality slow release product will suffice. Use fertiliser recommended for flowering plants.
PESTS AND DISEASE. Red spider or spidermite is troublesome in summer, especially in warmer climates. Control with Kelthane miticide, Pest Oil or predatory mites. Scale is easily controlled by Rogor, Malascale or Pest Oil. Always use at manufacturers recommended levels, if in doubt seek advice from a nursery or experienced grower.
AUSTRALIAN NATIVE ORCHID CULTURE -
DENDROBIUM AND SARCOCHILUS
The popularity of Australian Native Orchids has grown dramatically in recent years. New cultivars have provided growers with a broader range of colours and styles that are easy to grow and flower.
ENVIRONMENT. Found growing wild in most areas on the east coast of Australia it is easy to provide suitable conditions in this area. Dendrobiums prefer bright filtered light, 50%-70% shadecloth is ideal or a tree or similar screen allowing dappled sunlight is perfect. Sarcochilus are usually found in heavier shade areas, about 90% shade and somewhat higher humidity than dendrobiums is beneficial.
TEMPERATURE. New South Wales coastal temperatures are OK, good air movement is important, especially during very hot or cold periods so natural airflow should not be impeded. Sarcochilus enjoy temperatures up to 30 degrees, over this try to minimise maximum temperatures, by providing more shade or air movement.
WATERING. Perfect drainage is very important; many Australian Native Orchids grow on trees and dry off quickly after rain. Water thoroughly then allow plants to dry out completely before rewatering. Water regularly in summer, sparingly in winter. If you receive regular winter rain, a solid roof over plants may be necessary to control watering in cold weather.
COMPOST must be free draining. A coarse bark mix is ideal, perhaps add 20% gravel or similar if you wish. As a guide, use 10mm bark in 100mm pots, 15mm bark in 150mm pots and 20mm bark in 200mm pots or bigger. If established in the garden, a gravel bed under the plant will help with drainage, or attach firmly to a tree or rock and tie a pad of coconut fibre or similar over the root mass.
REPOTTING. Dendrobiums are best done soon after flowering, at the beginning of the growing season. We leave Sarcochilus till March/April after the worst of the hot weather has past. Sarc's grow all year, but experience most growth in this area during Autumn/ winter. Ensure pots have adequate drainage and are just big enough to contain the root system of the plant to be potted.
FERTILISE regularly, especially during the growing season, using a fertiliser for flowering plants, low in nitrogen and high in potassium.
PESTS AND DISEASE. Generally hardy and resilient, Australian Native Dendrobiums and Sarcochilus can sometimes be attacked by scale, aphid or spidermite. Treat with a recommended insecticide such as Diazinon or Pest Oil. Fungal infections are rare provided good air movement is maintained during wet weather.
are a group of plants that grow in shady, humid conditions throughout the Asian tropics and extend into northern Australia. They are arguably the most popular group of orchids grown in the world today, being particularly popular throughout the United States and Europe where they are regarded as one of the easiest orchids to grow indoors.
Temperature and Atmosphere Requirements. Phalaenopsis enjoy relatively stable temperatures. A minimum temperature of 15 degrees Celsius and a maximum of 30 degrees is optimal, however plants will tolerate temps of up to 5 degrees more extreme than this for short periods. Growing these plants outdoors in New South Wales will require some artificial heating in the winter and cooling in the summer. However their requirements fall almost perfectly within the comfort zone we enjoy inside the house. Phalaenopsis also require medium to high humidity. This can be achieved by placing the plants in a saucer of gravel, wet the gravel but be sure the base of the pot is above the water level. As the water evaporates, adequate humidity will be provided. Alternatively, mist the plants daily.
Light. Phalaenopsis enjoy low light and must be protected from direct, unfiltered sunlight. Outdoors sufficient shade so that on a sunny day a barely discernible shadow is cast is ideal. Indoors a brightly-lit room out of direct sun is suitable.
Watering and Fertilising. One of the secrets of growing Phallies is to keep the roots just damp but the leaves as dry as possible. This means that the compost should be allowed to nearly dry out before watering. After watering dry the leaves off as quickly as possible, especially any water lying in the crown of the plant where the leaves join. To help this avoid watering the leaves, or place the plants in a breezy spot for an hour or two after watering, even removing excess water from the leaves with a tissue will serve the purpose.
Fertilise with a recommended soluble orchid fertiliser at quarter strength every watering or at half strength every second watering. HSO 12 is ideal for all year round use.
Potting, Pests and Diseases. Keep plants in as small a pot as possible, a few roots growing out of the pot will not harm the plant and is not necessarily a reason to pot up the plant. Apart from crown rot, which can be avoided by careful watering, Phalaenopsis can suffer attack from Mealy Bugs. These appear as small furry white pests, usually under the leaves. They can be sprayed with Pyrethrum or a chemical insecticide such as Diazinon, or wet them with equal parts of Methylated spirits and water using a cotton bud or small cloth.
Phalaenopsis are very rewarding plants to grow and flowers last up to 12 weeks. When flowers have withered, cut the flower stem off between the third and fourth notch from the plant. The old stem will then shoot and flower a second time. Mature plants will flower twice each year so flowering can be achieved for up to half the year. Flowers are available in white, pink or yellow or with variations of spotting or veining on these backgrounds.
pronounced KAT-lee-uh, this group of orchids originates from a large area of tropical and sub-tropical America. They occur in many sizes, shapes and colours but are best known for their large flamboyant bloom. Most grow as epiphytes, or air plants. They have large pseudobulbs used to store water and have thick, fleshy roots that have the ability to collect moisture from the air.
LIGHT is important for good flowering. About 50% is optimal, however if leaves overheat in summer this may need to be increased to 70%. Leaves should be medium green colour and pseudobulbs rigid and erect without staking. Excessive shading will reduce flowering dramatically.
TEMPERATURE should range between a minimum of 5-7 degrees in winter to a maximum of about 30-35 degrees in summer. I suggest you avoid watering if the temperature falls below 10 degrees. Small plants need to be protected from temperature extremes. High day temperatures, up to 35 degrees can be tolerated if humidity, air circulation and shading are increased.
WATER can be provided in two ways, in the pot by watering and in the air by humidity. For a plant growing in good open media, watering twice each week in summer and once every two weeks in winter is sufficient. In summer avoid watering during the heat of the day, in winter only water on a bright sunny morning. The root system on these plants can easily be damage by excess water. If in doubt, defer watering.
HUMIDITY is important to Cattleyas, as roots prefer to grow in humid air rather than to be wet. Humidity needs to range from 50% to 80%, about 60% is ideal. In winter watering can be delayed by wetting the greenhouse floor and circulating air around the plants. This technique can also help to cool the plants in summer. If you live in a cool area, it may be necessary to grow your cattleyas under a solid cover so watering can be controlled during winter.FERTILISE with a balanced NPK (blossom booster) is ideal, apply in the water every second watering.
POTS should be shallow, ie no deeper than they are wide and should have plenty of holes to allow perfect drainage.MEDIA needs to be coarse and long lasting. Quality treated pine bark is most popular. As a guide use 10mm grade in 100mm pots, 15mm in 150mm pots and 20mm in 200mm pots or larger.
PESTS AND DISEASES. Cattleyas, apart from root rot caused by overwatering, can be attacked by pests such as scaly and mealy bug. This is easily controlled by Diazinon or Pest Oil. Slugs and snails love fresh root tips. Hanging plants or growing on mesh benches can help, but snail bait may be necessary.
SOFTCANE (NOBILE TYPE) DENDROBIUMS
Softcane, or Nobile type Dendrobiums grow naturally in Northern India & Thailand at elevations up to 1500 metres in the foothills of the Himalayan Mountains.
TEMPERATURE. These species and their hybrids are hardy plants that will tolerate temperatures from 3 degrees centigrade to temperatures in the high thirties.
WATER & FERTILISER. To grow softcane dendrobiums well, different seasonal treatment is required. After flowering in October increase watering & gradually increase fertiliser. Soluble 'flower-booster' fertiliser at recommended strength is preferred. By November when growths are 100mm or higher, water plants every second day and include fertiliser at least once per week. Maintain this treatment until new growths are nearly mature, say February or March. Reduce water & fertiliser so that by April, plants are receiving no nitrogen fertiliser at all. Water sparingly, just enough to prevent bulbs from shrivelling, until plants flower in Spring.
MEDIUM. Plants should be grown in well drained medium in pots as small as possible. Cover the plants with 30-50% shade in Summer to prevent burn to new growths, however plants will benefit from full or near full sun during Winter.
Softcane dendrobiums are easy orchids to grow provided they are given plenty of water & fertiliser in Summer, with no fertiliser, little water & plenty of light during Winter.
PAPHIOPEDILUM (SLIPPER ORCHIDS)
Paphiopedilums, more commonly known as Slipper Orchids, are shade loving plants from areas throughout Asia where they usually grow amongst rocks, moss and leaf litter in damp but well drained positions. Blooms are long lasting and are available in a range of colours. There are three main styles of flowers, popular amongst growers. These are the complex hybrids, which have large round flowers with broad segments and bloom during the winter. The second group is the maudiae types, which have attractive tessellated leaves and smaller flowers. The third group is the multiflorals, sometimes with 4 or 5 flowers on a stem. They have long strap like green leaves and are the slowest to grow.
TEMPERATURE AND LIGHT. Protection from frosts is necessary, especially for the maudiae and multifloral types; otherwise slippers are tolerant of a broad range of temperatures. Slippers thrive in conditions soft ferns such as maidenhair enjoy.
WATERING AND FERTILISING. Watering should be sufficient to keep the root system just damp. Short dry periods are OK but try to avoid over watering. As a guide, water every second day in summer and every 5-7 days in winter, depending on the weather of course. It is best to water during the morning in winter and evenings during summer. Include a balanced (flowering formula) fertiliser into the water at half the recommended strength, every second watering.
POTTING. A standard pot just big enough to contain the root system is adequate. Use a treated bark media that is coarse enough to allow good drainage but still remain damp for a few days. As a guide, in a 150mm pot use 10-15mm bark.
PESTS AND DISEASES. Slippers appear resistant to orchid virus. Fungus can develop on the leaves or in the leaf axils, usually due to overwatering. Mealy bug can sometimes attack leaves and roots but is easily controlled with Diazinon or similar. These plants are relatively pest free.
Paphiopedilums are attractive plants with curious but attractive flowers. They are very rewarding to grow in a shady, moist environment.
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