The Nobile Dendrobium is native to the highlands of South East Asia and the Himalayas. These plants are semi-deciduous, meaning that they lose a portion of their leaves at some point during their growing or flowering periods. These plants produce a profusion of sweet-scented blooms in the winter or early spring and can remain in flower for up to two months. Expired flowers should be removed by cutting them off at the point of emergence from the cane.
To ensure good growth and profuse flowering, Nobile Dendrobium requires bright light and prefers some direct sun. While growing in your home October through May, a very bright east exposure that receives ample direct sun is ideal or, a south or west exposure where the plant is receiving only a few hours of direct sunlight daily.
Nobile Dendrobium does best when grown outdoors during the months of June through October. Hang them from a tree or the overhang of your house, or place in a screened porch where they can receive some dappled sunlight. Nobile Dendrobium can benefit from higher intensities of light as the day length decreases towards fall and into winter, and vice-versa for the spring and summer. Try to provide as much light as possible for your plant throughout the year without causing sun burn on the leaves. Once your Nobile Dendrobium is in the flowering stage it is best to shade it from any direct sun to prolong the life of the blooms.
One important cultural element for the Nobile Dendrobium is that they do best when exposed to a 10 to 15 degree differential between day and night temperatures. It is for that reason we recommend to grow Nobile Dendrobium outdoors from June until early October. While growing outdoors these plants do not mind periodic temperature dips into the 50?s at night, as long as the temperature rises at least 10 degrees or more during the day. It would be time to bring your Nobile Dendrobium indoors once the temperature differential between day and night becomes narrow; for example when the October day time temperature is consistently 55 degrees and the nights are 50 degrees. Do not ever allow your Nobile Dendrobium to freeze.
Once you have brought your Nobile Dendrobium indoors for the growing season of October through May, it is best to place them in a sunny area that experiences a nighttime temperature of 55 to 60 degrees. In the home this can be best achieved by using a basement area or a spare room that you are able to reduce the nighttime heat source. For the day time, it is still important that the plant experiences a rise in temperature of at least 10 degrees or more. On cloudy winter days an artificial heat source may be needed to achieve the proper daytime temperature differential, while the sunny days should generate enough warmth for an adequate temperature differential. Keep in mind that the cool night time temperature in the late fall and early winter promotes the onset of the flowering period.
Proper indoor watering requires allowing the bark mix to become dry beneath the surface between watering cycles. Factors such as how root bound your pot is, how much light the plant is receiving, and what size pot it is in, will all play a role on how fast it dries out. Typically while growing indoors a good thorough watering once a week should be sufficient. In cases of root bound plants grown in warm, high light areas, watering every 5 days is needed. When watering, water the bark thoroughly until water runs freely from the bottom of the pot. Always remove your pot from any decorative container to allow for proper drainage. Never allow your pot to stand in any water as this will cause root rot. Never use softened water on any of your orchids.
For outdoor growing it is best to maintain slightly more moisture than for indoors. During the highest temperature periods (mid summer) we recommend to keep the Nobile Dendrobium moist but not soggy. A watering twice a week is usually needed during that period. As the temperature begins to drop towards the end of the outdoor season, begin letting the bark become dry beneath the surface, much like the indoor watering schedule. While outdoors the natural rain on the plant is beneficial.
The fertilizing program for the Nobile Dendrobium is perhaps one of the most important and regimented of many orchid types. Too much fertilizer causes the formation of what is commonly known as the Keiki, which in essence is the formation of an unwanted vegetative shoot emerging from the mid to upper section of the cane. If at any time your plant produces Keiki growths which protrude from the mid to upper section of the cane, they should be removed and discarded.
The proper fertilizing regimen for Nobile Dendrobium is to apply a 20-20-20 or similar balanced fertilizer once every 2 to 3 weeks from March through August. Discontinue fertilizing from September through February. A safe dilution ratio is one level teaspoon of fertilizer mixed in one gallon of water. Do not over-fertilize as this will cause permanent root damage.
Like most orchids, the Nobile Dendrobium enjoys a moderately humid climate of 50% or greater. While growing outdoors this is not an issue since we generally have adequate humidity in our Wisconsin summer climate. While growing indoors it is recommended to increase humidity around the plant simply by placing your plants on a humidity tray, misting them adequately in the morning, or grouping your plants all together in one area.
We recommend repotting Nobile Dendrobium every two years. If you are not experienced or comfortable doing this yourself we offer the repotting service at our greenhouse for a small fee. Your recently purchased Nobile Dendrobium may be ready for a repotting job as soon as it has finished flowering. Inquire with us as to when your individual plant was last repotted. Good indicators for a repot candidate are: when the rhizome and roots of the plant have protruded over the edge of the pot; when the potting medium starts to break down and drain poorly; or when the plant is completely root bound in the pot. It is best to repot just as new roots sprout from the rhizome which is typically after flowering has completed or during the spring and summer months as the plant becomes actively growing again.
Nobile Dendrobium may be divided if the plant has enough pseudobulbs (commonly called canes) to safely do so. A division should consist of four canes minimum, all still bearing healthy leaves. This will ensure that the plant will have enough strength for future growth. Larger divisions of 6-10 canes are preferred, which in turn will make for a specimen plant the next blooming season. If your plant is not dividable at this time simply repot it into a slightly larger pot.
To make a proper division, begin by examining your plant for a natural dividing line between the pseudobulbs that will give you equal halves, both having at least one new growth if possible. Using a large stiff knife, make a cut through the rhizome and root mass to make the division. Try to keep the root mass intact as much as possible as this will prevent transplant shock. Some leaf-less canes can be removed and discarded at this time, but it is important to keep your minimum number of canes to ensure a healthy division.
A note about orchid viruses: most commonly the transmission of orchid viruses is caused by using the same cutting tool on multiple plants. The most effective method to reduce virus transmission from plant to plant is to briefly flame sterilize all your cutting tools between use on each plant. A simple Butane torch or a gas stove are handy items for this purpose. This practice should be implemented when repotting as well as when cutting off expired flowering stems.
Once your division is made, select a new pot in the appropriate size to allow for another two years of growing. Unfortunately there is not a set rule for choosing the proper pot size, but generally you will need to increase the pot size by one to two inches. Do not use too large of a pot because these plants like to be somewhat crowded, even after repotting. The Nobile Dendrobium prefers to be potted into clay pots for the benefit of the porosity offered by the clay as well as the stability from the weight.
Place the plant into your selected pot and add our moistened fir bark orchid potting mix around the roots. Position the plant in the pot so the junction of the plant and roots is buried one half inch below the potting mixture. Pack the potting mixture firmly with a blunt tool to ensure the plant is secure in the pot. Wait about one week and then water thoroughly.
For more assistance with your Nobile Dendrobium or any other Orchid, please call us at 608-831-4700, send an email, or visit our store!
Happy growing, from Orchids Garden Centre & Nursery!