Horticulture Magazine

Dendrobium Orchid Care & Growing Tips

purple dendrobium flowers in singapore

Dendrobium Overview

Official Plant NameDendrobium
Common Name(s)Dendrobium Orchids
Plant TypeHouseplant
Native AreaSouth-East Asia
Hardiness RatingH1A – H1C
ToxicityRare allergies possible
FoliageEpiphytic in nature
FlowersVarious orchid blooms
When To SowMarch, April, May
Flowering MonthsApril, May, June
Sunlight

Preferred
Full Sun

Exposure
Indoors

Size

Height
0.1 – 0.5M

Spread
0.1 – 0.5M

Bloom Time
April – June

Soil

Preferred
Loam / Orchid Medium

Moisture
Well Drained

pH
Neutral

With their dark green foliage and distinctive, tropical flowers, it’s not hard to see why orchids are one of the most popular container plants in the UK.

Dendrobium orchids are a genus of epiphytic orchids, known for their linear leaves and attractive sprays of showy flowers.

There are over 1000 species of Dendrobium orchids, and they all have slightly different appearances and care requirements – although they can be roughly grouped into the cooler-growing varieties, and the warmer-growing varieties, that need heat to thrive.

Dendrobium orchids are not difficult to grow, but they do require ongoing maintenance to flower and look their best. This includes regular watering, feeding with a specialised orchid food, and misting, to recreate their natural humid habitat.

If you’ve recently acquired, or are thinking about acquiring, a Dendrobium orchid, read on for our full care and growing guide, to find out exactly how to look after your pretty new flower plant.

Background, Origins & Varieties

Dendrobium is part of the Orchidaceae family. They are terrestrial and epiphytic, meaning that they grow on other plants and rocks, rather than in soil. Some Dendrobium orchids are deciduous, and some remain green year-round.

The name ‘Dendrobium’ is derived from the Ancient Greek words for tree, ‘Dendron’, and life, ‘Bios’, and refers to the fact that these orchids are often found growing on tree branches in their natural habitat.

There are approximately 1200 species of Dendrobium orchids, and many hybrids, making them one of the largest genus of orchids. Some grow well in cooler conditions, such as D. nobile, and others prefer hot temperatures, such as D. bigibbum.

Dendrobium orchids flower in spikes, from the old pseudobulbs (canes), and either alone or in racemes. Most varieties produce flowering spikes of around 30 – 50cm, but some larger varieties can grow up to 120cm tall.

Plants generally bloom for 6 – 8 weeks. The colour of the blooms ranges greatly depending on the variety, and includes red, purple, pink, yellow and white. They can also be a mix of 2 of more colours. D. nobile has white, rose pink or purple flowers with a contrasting lip, and can produce up to 50 blooms per stem. This variety is often used in traditional Chinese medicine.

This Dendrobium nobile has a distinctive, contrasting maroon lip
This Dendrobium nobile has a distinctive, contrasting maroon lip

Feeding, Care & Growing Tips

Dendrobium orchids grow best in small pots, and therefore work well as patio, greenhouse or indoor plants. They like their roots to be crowded, so you should select a pot that is no more than 3cm bigger than the plant’s root ball. Do not plant it directly in the ground, and do not use a generic potting compost.

As Dendrobium orchids are epiphytic, you will need to source a special epiphytic orchid compost to plant them in. Alternatively, you can also pot in a different material, such as moss, tree bark or coconut husks. These orchids must have good drainage – it can be helpful to plant them in hanging baskets to ensure this.

The best temperature to keep your Dendrobium orchid at depends on whether it’s a cool or warm-growing variety. Generally speaking, cool-growing varieties need to be kept above a minimum night temperature of 10°C, whilst warm-growing varieties should be above 21°C. You will find it easier to control the temperature if you keep the plant indoors.

Light is very important for Dendrobium orchids. Your plant will need access to full light between autumn and spring, in order for its canes to ripen. This light can come from natural sunlight through a south-facing window, or specially set up grow lamps. In summer, it’s best to keep the plant in partial shade to avoid it getting too warm.

During the summer growing period, you will need to water your orchid weekly, or whenever the soil starts getting dry. You should also aim to mist it once or twice a day, to replicate the humidity of its natural habitat. Every second watering, add a specialised orchid fertiliser to the water, to give it a boost of the nutrients essential for flowering.

Warm-growing species will need to be watered throughout the winter too, but cool-growing species can be kept drier, as they enter their winter dormancy period – it is essential to research the requirements of your particular variety. Make sure never to allow your orchid to become waterlogged, or to sit in water, as the roots are prone to rotting.

Dendrobium should be disturbed as little as possible, especially once their flowering spike has appeared. If they outgrow their container and need to be re-potted, the best time to do this is in spring, or at the beginning of the plant’s growing season.

Pruning Dendrobium

Dendrobium orchids do not need to be pruned, and older canes often store water and nutrients essential for plant health. The plant can also flower on old canes. However, you can manage their size and keep them looking their best by trimming the old flowering stems if necessary, using sharp scissors.

When To Plant

The best time to plant a Dendrobium orchid will depend on the variety you’re growing. As a general rule, it is best to plant at the beginning of the growing season, which is often in spring. This is also true if you are re-potting the plant, or propagating it through division.

You should plant your Dendrobium orchid in a special epiphytic orchid compost, or a soil alternative such as moss, coconut husks or tree bark, to replicate their natural epiphytic growing conditions.

Always plant in a small pot, as Dendrobium likes its roots to be constricted, and this will also help to prevent the plant from becoming waterlogged. You can always place the small pot inside a larger container if you prefer this look.

Habitat & Growing Conditions

Orchids are found all over the world, with different species originating from different locales and climates. Most Dendrobiums, including Dendrobium nobile, originate from South and South East Asia.

Dendrobium orchids grow in everything from warm, humid forests, river valleys, dry deserts, and cool, high-altitude mountainsides, such as in the Himalayas. As they are epiphytic, they are usually found growing on other plants, such as trees, or on rocks.

They generally need a lot of moisture in the air, but not at their roots, as they do not like to be waterlogged and are prone to root rot. You can replicate these conditions at home by misting your orchid’s leaves with water, using a spray bottle.

Misting an indoor plant with a water sprayer
Mist your Dendrobium’s leaves to replicate its natural humid growing conditions

Where To Buy

You can buy Dendrobium orchids from garden centres, nurseries, or online suppliers. Two of the most commonly available types of Dendrobium orchid in the UK are Dendrobium nobile and Dendrobium bigibbum.

As there are over 1000 different varieties, and many more hybrids of Dendrobium orchid, if there is a particular colour or variety you want, you may need to seek out a specialist grower.

Another way to acquire an orchid, other than buying it, is to propagate an existing plant. This could be a good option if you have a friend or family member who already owns a Dendrobium orchid.

How To Propagate Dendrobium

The best way to propagate Dendrobium orchids is by division, in spring. Ideally, this should only be done once the orchid has outgrown its current pot, and re-potting is absolutely necessary, as orchids do not respond well to being disturbed. You should also make sure your orchid has enough canes to make division viable.

To propagate a Dendrobium, you should first carefully remove it from the soil, then gently pull the root ball apart, to create two plants. Re-plant immediately after division, either into the same soil, or new epiphytic orchid compost. Water the propagated plants well, but ensure the soil can drain, so it does not become waterlogged.

Common Diseases & Problems

There are several pests you should watch out for on your Dendrobium orchid, including aphids and glasshouse red spider mite, which is encouraged by Dendrobium’s warm and humid growing conditions.

Dendrobium is also prone to mealybugs. If your plant has an infestation, you might notice the tiny 0.5mm bugs, or miniscule yellow spots on the leaves. To combat an infestation, clean the plant carefully with cotton wool dipped in rubbing alcohol, and repeat after 2 days.

One way to help prevent pests in your orchid is to ensure it has plenty of space for air to circulate around it – you could even use a fan if necessary, to promote this. Other than pests, there are not many common diseases you need to worry about with your Dendrobium.

Probably the most common problem growers encounter with Dendrobium orchids is dry leaves. If your orchid’s leaves look dry or have brown tips, it is most likely due to low humidity.

You can increase the humidity around your plant by using a humidifier – its ideal humidity level is 50 – 70%. If your plant’s leaves are yellow, it may also be too warm, so move it to a cooler location, out of direct sunlight.

Frequently Asked Questions

Are dendrobium orchids poisonous to dogs?

Dendrobium orchids are not generally considered poisonous to dogs. However, as there are so many varieties and hybrids, it is not impossible that your dog may experience a reaction to a compound in a particular variety. There are also other plants commonly referred to as orchids, such as the lady slipper orchid, that may cause irritation to your dog.

It is therefore a good idea to prevent your dog from eating any orchids or orchid-like plants, if at all possible. If you suspect your dog has eaten an orchid, monitor them for signs of gastronomical distress, and seek veterinary advice if they display any adverse symptoms.

When do dendrobium orchids bloom?

Exactly when your dendrobium orchid will bloom depends on the variety and growing conditions. There are over 1000 species of Dendrobium orchid, and their flowering period varies. Cool-growing varieties such as D. nobile tend to bloom in late winter and spring. Some other varieties will bloom multiple times throughout the year.

How can I get my dendrobium orchids to bloom?

To encourage your Dendrobium orchids to bloom, you should feed them a specialised orchid fertiliser with every second watering. Dilute this according to the plant food manufacturer’s instructions, to avoid burning your orchid’s roots.

Your orchid’s fertiliser should container a good balance of nitrogen, phosphorus and potassium, all essential nutrients for growth, as well as other important minerals, such as calcium and magnesium, and trace elements such as iron and zinc.

In addition to feeding your orchid, make sure the rest of its growing conditions are being met. Water weekly (but avoid letting the soil become waterlogged), mist daily, and ensure you are meeting its temperature requirements. Sometimes, a slight drop in nighttime temperature can trigger your orchid to bloom.

Light is also particularly important for flowering – your orchid is unlikely to bloom well unless it is getting enough light to allow its canes to ripen. Move your orchid to an area with good natural light, or if this is not possible, use grow lights to give your orchid 15 hours of light a day.

Are blue dendrobium orchids natural?

Blue Dendrobium orchids are not natural, as orchids do not naturally produce true blue or black flowers. When you see bright blue orchids, what you are usually seeing is white orchids that have been dyed blue, by injecting food colouring into the flowering stem. If the plant flowers again, any new blooms produced will be the original white colour, not blue.

Blue orchids dyed with food colouring
Blue orchids are usually dyed with food colouring

Are dendrobium orchids safe for cats?

Dendrobium orchids are not considered toxic to cats and are therefore safe to have in a house with cats. However, it is still a good idea to keep your cat away from the orchid, to prevent damage to the plant, and to avoid any risk of discomfort to your cat that might be caused by ingestion.

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