History & Interesting Facts:
Oncidium orchids are native to the lush jungles of Central and South America, both in low-lying coastal areas, and as high as 8 000 feet in the Andes Mountains. They are also found throughout the tropics, from Florida in the U.S. all the way to Brazil, Ecuador, Peru, and Argentina. In their natural habitat, the various species can be seen growing attached to trees as epiphytes, on the top of rocks as lithophytes, and someare terrestrials found growing on the forest floor.
Oncidium orchids were first officially described by Olaf Swartz, a Swedish botanist, in the year 1800. The name Oncidium was taken from the Greek word “onkos” which means “swelling or mass,” referring to the uniquely shaped bump on the lips of its flowers.
The Oncidium Alliance
According to the American Orchid Society Oncidium is a genus of the orchid family (Orchidaceae) that contains at least 300 recognised species from the subtribe Oncidiinae.
Oncidium orchids are members of what is called the “Oncidium Alliance”. An alliance is a group of different orchid genera that possess a lot of similarities and which can be crossbred, and the Oncidium alliance is comprised of over 1 200 orchid species from as many as 70 orchid genera.
The biggest numbers are from orchid species of the Oncidium and Odontoglossum genera. Other well-known orchid genera that belong to this alliance include Brassia, Miltonia, Miltoniopsis, Psychopsis, Trichopilia, and Tolumnia among others.
Click here to see Google images of Oncidium Orchids
Click here to see Google images of Odontoglossum Orchids
Click here to see Google images of Brassia Orchids
Click here to see Google images of Miltonia Orchids
Click here to see Google images of Miltoniopsis Orchids
Click here to see Google images of Psychopsis Orchids
Click here to see Google images of Trichopilia Orchids
Click here to see Google images of Tolumnia orchids
Oncidium Intergeneric Hybrids
Intergeneric Hybrids are created by crossing orchids from different, unrelated genera.
An excellent example of this would be Oncostele Wildcat, formerly known as Colmanara Wildcat. It is an intricate intergeneric orchid hybrid made of Oncidium, Miltonia, and Odontoglossum. Burrageara Nelly Isler and Odontocidium Mitsuishi are other recognized intergeneric hybrids.
Click here to see Google images of Oncostele Wildcat Orchid
Description:
Today, there are over a thousand named Oncidium orchid hybrids in many sizes, shapes, and colours. They are fondly nicknamed “dancing lady orchids” for the shape of their large flower petals that flutter in even the slightest breeze and resemble ladies dancing in flowing skirts. Another common name is “Tiger Orchid”.
When do Oncidium orchids bloom?
Blooming times of Oncidium orchids can vary a bit, depending on the species, but is generally in autumn and winter.
What flower colours do Oncidium orchids have?
Although the majority of Oncidium orchids are more commonly available in shades of yellow, and brown, stunning sprays in white, pink, red, green, and purple are now emerging. Some species of Oncidium orchids are also blessed with a pleasant scent.
Flowers usually blossom in many sprays, and in multiple long spikes which can grow seriously long, up to 3.5m, with a spread up to 60cm. A couple of exceptional varieties like Oncidium altissimum and Oncidium baueri can reach up to 4.5m long!
Click here to see Google images of Oncidium altissimum
Click here to see Google images of Oncidium baueri
Oncidium Orchid. Picture courtesy Lotus Johnson from flickrCultivation:
When caring for orchids it is helpful to think of them growing in their natural environment, as the vast majority of cultivated orchids originate from tropical climates and cloud forests with high humidity and constant air movement.
As with other amazingly large and diverse orchid genera, dancing lady orchids can grow and adapt in a wide variety of habitats and under different environments and conditions. Due to the wide distribution of this species in the wild, and the vast number of different habitats, it’s difficult to generalise the growing conditions required.
For example, in the warmer regions of South Africa, hybrids bred from the intermediate to warm growing group of Oncidiums are selected, and in our cooler regions hybrids requiring cooler temperatures are grown. Therefore, for specific care instructions it’s worthwhile to purchase your orchids from a specialist grower.
That being said, Oncidium orchids are no diva’s and are known to be easier to take care of and propagate compared to their half brothers and sisters from the Odontoglossum and Miltoniopsis genera.
What are the optimal temperatures for growing Oncidium orchids?
Temperature may be the most important factor to get right when growing these orchids, as they won’t tolerate cold spells for long. Night temperatures should not drop below 15°C, and the daylight temperatures should not exceed 30°C, unless there is high humidity and air movement is increased proportionally.
Why do orchids require humidity?
Humidity is the percentage of water vapour in the air and you have most likely observed that humidity is lowest during the day and highest in the evening and morning. Orchids, like all plants have stomata or pores on their leaves that allow them to breathe by absorbing carbon dioxide and releasing oxygen. So, when orchids open their stomata to breathe they lose water, and in their native rainforests, humidity compensates for the water lost when opening their stomata.
If humidity levels are too low this means that the water loss through the stomata is greater than the water absorbed through the roots, resulting in a drought situation. In response to low humidity levels, the orchid closes its stomata and stops absorbing carbon dioxide. In essence, it stops breathing!
Orchids require water vapour in the air, and you cannot compensate for a lack of humidity in the air by increasing water to the roots.
If you live in our humid subtropical regions Oncidium orchids will thrive indoors or outdoors with little effort. However, in colder, less humid regions of the country will they need some extra TLC.
The challenge for those of us who grow orchids in our homes is that most orchids require a minimum of 45 to 50% humidity, and even the so-called ‘low humidity orchids’ need humidity levels around 40%. Luckily Oncidium orchids fall under this group that will thrive indoors with humidity levels between 40 to 50%. The recommended humidity for our homes is between 30 to 50%, so it is possible to find that ‘sweet spot’ inside to grow orchids.
If you live in an arid summer rainfall region, it may be a bit of a struggle to maintain even 30% humidity in winter it, but Oncidium orchids will tolerate this. In these regions it would be best to increase the humidity level in your orchid room year-round.
How to increase humidity indoors and outdoors
Desiccation, or leaf drop, is an indication of both too much and too little humidity. So if the leaves of your orchid are dropping don’t assume it needs more humidity, rather look for these other symptoms. If the roots are rotting, humidity may be too high, but if the pseudobulbs are wrinkly and shrunken, humidity may be too low.
Click here to see pseudobulbs of Oncidium Orchids
It’s easy to increase humidity outdoors and in a greenhouse by turning on misters, and in a greenhouse you can just spray down the floor for higher humidity.
Group plants together
Grouping pot plants together indoors increases humidity around the plants, creating a mini microclimate, but take care not to overcrowd the plants, giving them sufficient space so air can move freely around them.
Make an orchid humidity tray
One popular way to increase humidity is to make a humidity tray for orchids. Simply find a drip tray or any watertight bowl that you can fill with small pebbles or gravel. Pour water into the tray until it is about halfway full and the orchid pot can stand safely on the gravel above the water line, and not in the water. If an orchid’s roots sit in water they will rot and die. This method allows the water to evaporate and creates a small microclimate around the plant.
Does hand misting increase humidity
Orchids, and particularly those that are mounted will benefit from regularly misting of their roots, but not really their leaves. In fact, misting orchid leaves to frequently indoors can lead to infection if there is little or no airflow.
Hand misting around the plant is also only a temporary fix and will not raise the humidity levels around the plants for long.
Use a Hygrometer and Humidifier
If you live in a dry region purchasing a digital indoor hygrometer which measures both temperature and humidity would be a worthwhile investment if you wish to grow orchids indoors. You can purchase these at any local home goods store or online.
When using a humidifier, follow the manufacturer’s instructions to ensure that undue moisture does not accumulate. If your windows and mirrors have condensation this is a sure sign that the humidity is too high. To reduce fungal and bacterial growth, keep your humidifier clean. Follow the manufacturers’ instructions as regularly cleaning your humidifier will reduce the amount of fungus and bacteria in the air. Purchase a humidifier with the largest water tank that you can afford. This will reduce the number of times that you will have to refill the tank.
Why orchids need good air flow
If you are serious about growing orchids you need a fan, as airflow is the counterbalance to humidity. Orchids need humidity to breathe and, just as importantly, orchids need good air movement to stay healthy. Disease, mould, fungus, and bacteria all have a harder time taking hold of your orchid with a steady, yet gentle airflow around them. Together, humidity and airflow will create a healthy climate for orchids.
If you only have only one orchid, opening a window may be sufficient, but a small fan is your best option if you have a few orchids. Simply turn the fan to the lowest setting and face it away from the plants as pointing a fan directly at the orchids can be too drying.
How much light do Oncidium orchids require?
Whether you are growing them indoors or outdoors, Oncidium orchids love to be where they will receive shaded to bright indirect light. Placing them in front of a north facing window with sheer curtains that can shelter them from intense heat would be perfect, and an east facing window that receives morning sun would also be good.
If your plants are not receiving sufficient light, investing in grow lights would solve this problem.
Use the leaves of your orchid as an indicator if it is getting an adequate amount of light. Leaves should be a grassy light green colour. Yellowing leaves means too much light exposure and dark green leaves suggest it’s getting too little light.
How to water Oncidium orchids
Water your orchid about every 7 days during the warmer summer months, allowing the roots to dry in between watering sessions. During winter, you can cut back on watering to about twice a month.
Thin-leaved Oncidium orchids should be water more frequently compared to species with thick, fleshy leaves.
Don’t overwater Oncidiums as they are drought-resistant orchids that have huge pseudobulbs that serve as water tanks. Wrinkled pseudobulbs indicate a lack of water.
Room temperature water is best, but some gardeners water their orchids with ice cubes without harming the plant. About once a week, place up to three ice cubes on top of the potting medium, preferably where the cubes don't touch the leaves – easy!
Can tap water be used on orchids?
Tap water is perfectly fine for orchids, as long as the water is soft and the pH is neutral. If your tap water is hard add a water softener, or use filtered water.
If you boil tap water in a saucepan or kettle, the limescale will simply settle at the bottom.
Many orchid growers use rainwater, and this is probably the best as rainwater it is low in dissolved solids and the pH is balanced. If there is little pollution where you live, it should also be fairly free of additional chemicals.
How to fertilise Oncidium orchids
Depending on your growing medium, and which fertiliser you are using, Oncidium orchids should be fertilised once a week, or fortnightly in summer and less in winter. In bark based soils feeding every time you water may be necessary during the summer growing season.
Some Oncidiums require a rest period in winter and should not be fertilised, so it’s best to check with your plant supplier for your orchids requirements.
Dancing lady orchids can be fertilised with a specialist orchid food or with Multifeed P, Pokon, Nitrosol or Seagro, at the recommended strength.
Be careful with over fertilization, as it can burn your orchid’s fragile roots.
Pruning Oncidium orchids after flowering
After the blooms fade, it's decision time. If the spike is green, cut it back to just above a node. If it's spent, say goodbye and cut it down to the base. Some Oncidium species are known to produce flowers on the same spike for many years.
When to repot Oncidium orchids
Do not repot unless absolutely necessary, as orchids have thin sensitive roots that can be damaged. Usually, orchids don’t need to be transferred to another pot for at least two years.
Repotting should be done when new root growth appears at the base of the pseudobulbs, and there are at least 6 pseudobulbs. A pseudobulb is a storage organ found in many epiphytic and terrestrial sympodial orchids. It is derived from a thickening of the part of a stem between leaf nodes
Click here to see pseudobulbs of Oncidium Orchids
How to repot Oncidium orchids
Oncidium roots are very delicate, so handle carefully when repotting. Remove the plant from the pot and gently shake or tease the old potting soil off the roots. Use a sharp clean knife or pruner to cut off any dead or unhealthy roots, which may be brown, soft or papery. Healthy roots should be white and firm. Replant into a clean container with fresh growing medium.
If you are using pots, terracotta pots are the best because they allow the soil to breath. Hanging baskets are also perfect for growing these orchids to show off their impressive sprays of cascading flowers best.
What potting medium is best for Oncidium orchids
If your orchids need repotting it means they have survived, congratulations! To ensure that they continue to thrive, it’s really worth the expense of purchasing a specialised orchid mix. In their natural habitat, orchids grow with their roots in the air, which is why they can easily go brown and rot in the wrong soil.
Pokon Orchid Mix is wonderful because it has been created for growing all varieties of orchids, by mixing only the best quality, natural raw materials, such as French Bark and turf granules. The Mix also contains enough plant food for approximately 60 days.
Oncidium Picture courtesy Joel Abroad from flickrHow to mount Oncidium orchids
If you live in our humid subtropical regions you can grow Oncidium Orchids outdoors, and like other epiphytic orchids, they are often attached to the bark of living trees. They are not parasitic and do not take away minerals from the tree, but absorb moisture and nutrients from the air.
Selecting just the right material to mount your collection on is most important because your orchids are going to be growing there for a long time, so choose material that is not going to deteriorate and fall apart just when they have rooted and are beginning to flourish.
They root easily on rough surfaces, making rocks, hardwood tree stumps or logs, and driftwood ideal to mount on, not forgetting cork which is used to hang plants on walls, or from ceilings.
Make sure whatever surface you are going to mount onto is clean and clear of any other organic material. Scrub off any moss or fungi with a brush and spray the surface area with a hose. This helps to keep the plants safe from diseases and gives them a nice surface to grow into.
Any driftwood that was taken from the beach should be soaked in fresh water for a few days to remove salt from the surface, changing the water occasionally. Orchids are much less likely to attach if there is too much salt and their roots could become dehydrated.
Orchids will not be able to attach onto any surface if they are not attached firmly, as even the slightest sway from a breeze can jar the plant and prevent the roots from attaching. Therefore, it is important to use the right material to attach an orchid securely.
A natural jute garden twine is highly recommended as it is organic and will rot away on its own, making it better for the environment, and you don’t have to worry about the twine cutting into the plant or the stem. It is also great to use because it will swell and shrink with the stem when wet and dry, providing a better hold. The downside of using twine is that if it gets too wet too often, it may rot and break its hold before the plant has had sufficient time to attach fully. If you are worried about this, tie the plant on with jute garden twine and lastly tie a few pieces of wire (not copper) around the plant and its mount, just to be sure. The wire can easily be cut off later.
Using round cable staples is a fantastic method for attaching orchids, because you can find them in different sizes and the round shape conforms to the stem. The staples will last long enough for the plant to attach itself, are almost invisible, and normally you will need to use only two or three per plant. The only downside is that they can damage the plant if you use a staple which is too small, and it cuts into the stem. The staples will rust away naturally but the rust doesn’t seem to harm the plant at all.
Fishing line is commonly used as a way to mount orchids, but many growers do not recommend it because, although it is very strong and hides well, it will not disintegrate, and unless removed will last for life. This can create problems as the plants grow and spread, potentially cutting into the stem and preventing other pups from attaching. Fishing line is also not elastic, so it will not shrink like twine does with the stem when it gets dehydrated, and just this little movement can lengthen the time to attach by months.
A non-copper wire is also often used, and although it is strong and some wire may eventually disintegrate, it can be difficult to get the wire tight enough to hold the plant firmly without cutting into the stem, and like fishing line it is also not elastic, and can cause delays in attaching as the stem shrinks and swells.
Select a piece of orchid that is small enough to be supported only by its stem, as this will allow the roots to grow with the plant, and the plant will attach much easier. Plants which are too large will be top heavy and will not attach easily. Wash off any growing medium before pruning the roots back as much as possible. This allows the orchid to spend energy growing new roots which will attach easier.
Wrap the roots with some sphagnum moss, and find a nice nook in your driftwood or rock to tuck the root system into. Hold the plant in place – here is where it helps if there are two of you, one to hold the plant in place while the other ties it down, but it can be done alone. Next, take some strong twine and wrap it around the roots and the driftwood until the plant is held down firmly, but not so tight as to damage the plant.
Water the plants thoroughly, using a soft spray, and place your new orchid display in a location that gets plenty of light and check the plants daily, watering as required. It can take anywhere from 1 to 6 months for orchids to attach, depending on the growing conditions.
Water and feeding as recommended above, and keeping the plants free from debris like fallen leaves or twigs, will help the roots grow quicker and stronger. Once the plants have fastened their roots the wire can be cut and removed, but if you have used twine it can be left to disintegrate on its own.
Remember that mounted orchids growing outdoors require high humidity and more frequent watering than potted plants indoors. and if grown in dry climates outdoors, the plants will benefit from frequent misting of the roots with water.