Horticulture Magazine

Dendrobium Orchid

purple dendrobium flowers in singapore
By APRIL FOOT
April Foot, BA (Hons) - Gardener

April is a writer specialising in gardening and the environment. She is an avid wildlife-enthusiast and adventure-seeker, and feels happiest when in the Great Outdoors. April graduated from the University of Southampton in 2013 with a BA (Hons) degree in English.

/ Updated June 26th, 2023
Reviewed By DAN ORI
Dan Ori, MCIHort, Horticulturist

Dan has over 27 years’ under his belt caring for plants and gardens. Working as a Horticultural Instructor and Consultant, he draws on a diverse range of experience that includes working as a Head Gardener, Tree Surgeon, Garden Centre Trouble Shooter, and writer of academic papers. Dan has a Level 3 Diploma in Horticulture and is currently a candidate for the RHS’s most prestigious award – The Master of Horticulture.

/ Meets Our Editorial Guidelines
Contributions From SARA RITTERSHAUSEN
Sara Rittershausen, Owner of Burnham Nurseries Ltd

With several published books on the topic of orchids, Sara is the owner of Burnham Nurseries Ltd, one of the UK’s leading orchid sellers that first opened over 70 years ago. Sara has worked for the nursery for 32 years, during which time she has won various awards, most recently winning a Gold Medal at the RHS Wisley Orchid Show in 2022.

, PAUL UPWARD
Paul Upward, Chairman and Programme Secretary of the Thames Valley Orchid Society

The Chairman and Programme Secretary of the Thames Valley Orchid Society, Paul is also a professional photographer with a big interest in orchids. He owns over 200 plants which he keeps in his orchid house!

, DANIEL TOOR
Daniel Toor, Owner of The Dark Orchid

Daniel is the owner of The Dark Orchid, a specialist orchid seller that ships exotic and rare orchid varieties throughout the UK. Some of the orchids for sale can be found on his Instagram page, where he shares photos of some stunning varieties.

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.

In this guide, we collaborate and share advice from three recognised orchid growers and sellers:

  • Sara Rittershausen – Owner of Burnham Nurseries Ltd.
  • Paul Upward – Chairman and Programme Secretary of the Thames Valley Orchid Society.
  • Daniel Toor – Owner of The Dark Orchid.

“Beyond their beauty, it’s the delicate care and attention required to cultivate these magnificent plants that makes growing them so rewarding, with blooms as a final prize,” says Daniel.

“In many ways, orchids are like beloved pets that require constant nurturing and attention, rather than mere houseplants.

“Their unique needs and characteristics make them fascinating subjects for both novice and seasoned gardeners alike.”

There are over 1,000 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.1Dendrobium. (n.d.). American Orchid Society. Retrieved March 14, 2023, from https://www.aos.org/orchids/orchids-a-to-z/letter-d/dendrobium.aspx

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.

Overview

Botanical NameDendrobium
Plant TypeHouseplant
Native AreaSouth-East Asia
Hardiness RatingH1A – H1C
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

Dendrobium is part of the Orchidaceae family.2Dendrobium (group). (n.d.). Missouri Botanical Garden. Retrieved March 14, 2023, from https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=b625

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.3Dendrobium spectabile. (2020, May 22). Hawaii Tropical Bioreserve & Garden. Retrieved March 14, 2023, from https://htbg.com/dendrobium-spectabile/

pink Dendrobium orchid flowers hanging from the trunk of a tree

“The orchid family is huge and there really is something for everyone, as there is always something different in each flower to enjoy and new ones to learn about,” shares Sara.

“The variety and diversity of the orchid make it the most fascinating plant family.”

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.

Dendrobium nobile flowers with a distinctive, contrasting maroon lip
This D. nobile has a distinctive, contrasting maroon lip

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 two or more colours – D. nobile has white, rose pink or purple flowers with a contrasting lip, and can produce up to 50 blooms per stem.

Habitat & Growing Conditions

Orchids are found all over the world, with different species originating from different locales and climates.

Most Dendrobiums, including D. nobile, originate from South and South East Asia.

Dendrobium Nobile orchid flower with pink and white petals

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.

“Grow other houseplants with them as they will enjoy the environment this creates,” suggests Sara.

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

“Your orchid will also need bright, indirect light to thrive, so place it near a window or provide additional artificial light,” Daniel says.

How To Grow Dendrobium

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 D. nobile and D. bigibbum.

Dendrobium bigibbum flowers in pink

As there are at least 1,000 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.

“When it comes to growing orchids, there’s no one-size-fits-all answer,” says Daniel.

“With so many different species, each with its own specific requirements, the key to success lies in understanding the unique needs of your plants.”

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.

Container & Potting Medium

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.

the root system of a large dendrobium orchid ready for transplanting

As Dendrobium orchids are epiphytic, you will need to source a special epiphytic orchid compost to plant them in.

“To help prevent overwatering, make sure your orchid’s potting mix has proper drainage and only water the plant when the mix is dry to the touch,” says Daniel.

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.

Planting

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.

root system of a dendrobium orchid

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.

“Many a Dendrobium have met their end by planting them in heavy orchid composts and allowing them to sit in water,” says Horticultural Consultant Dan Ori.

“Although they can tolerate growing in an orchid compost with some soil or broken-down bark if you are light on watering, I find it best to have them in a low-absorbent material like bark chip.”

Dendrobium Care

“The challenge of getting these magical, mysterious and temperamental plants to grow well and flower is what makes them so rewarding,” shares Paul.

“Orchids can be tricky to grow and when I get it right, I feel a great sense of achievement. Every orchid enthusiast has at some point killed plants because the conditions they gave them weren’t to the plant’s liking.

“They could be kept at the wrong temperature, received too much or too little light, or received too much fertiliser.

“However, over time I learnt from other growers, I joined orchid societies, read books and searched websites. 

“Making one small change at a time to my growing conditions, the plants grew more vigorously, flowered more regularly, and I began to win more awards at shows.”

Temperature & Sunlight

The best temperature to keep your Dendrobium orchid depends on whether it’s a cool or warm-growing variety.

beautiful pink flowers of Dendrobium nobile

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.

“Orchids tend to bloom when conditions change,” says Paul.

“Often, it’s as a result of temperature change. When winter arrives, many orchids start to flower, or it can be as simple as a change in temperature between night and day.”

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.

soft cane orchids in flower

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.

Watering & Feeding

“Watering is a delicate balance and is essential to the health and growth of your orchids,” says Daniel.

“Finding the right balance can be challenging, but it’s crucial for keeping your orchids thriving.

“To get it right, it’s important to consider factors such as the type of orchid you have, the size of the pot and the environment it’s growing in.

“With proper care and attention, you can keep your orchids healthy and gorgeous for years to come.”

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.

woman shown misting a potted Dendrobium orchid

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.

“Try giving a high-potash orchid bloom feed to encourage ones that have not flowered for a while,” says Sara.

pink and white Dendrobium orchid flowers

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.

Propagation

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.

blue scissors being used to take cuttings from a pink flowering orchid

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 Problems

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

“Some common problems that orchid enthusiasts face include overwatering, poor lighting, pests, and nutrient deficiencies,” explains Daniel.

“However, these challenges can be easily overcome with a little bit of care and attention.”

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.

“Pests like spider mites and scale insects can be a problem for orchids, but regular inspections and prompt treatment can help keep them at bay,” shares Daniel.

“And, to make sure your orchid receives the nutrients it needs to grow and bloom, be sure to fertilise it regularly with a balanced fertiliser.”

One other way to help prevent pests with 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.

orchid leaves dry and yellow with affected black spots

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.

“Orchids sulk when they’re not happy with the conditions you offer them,” explains Paul.

“When they’re not happy, they soon let you know. The plant becomes weak, leaves can turn yellow, leaf tips can go brown and soon the plant becomes susceptible to pests such as mealy bugs.

“When orchids start to show signs of being stressed, it can be tricky and time-consuming to return them to good health.

“It’s therefore important that you check your plants regularly to catch any issues before they take hold.”

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.

FAQs

When Do Dendrobium Orchids Bloom?

Exactly when your dendrobium orchid will bloom depends on the variety and growing conditions.

There are over 1,000 species of Dendrobium orchid, and their flowering period varies.

white and purple Cooktown orchid

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.

Purple dendrobium orchid in bloom

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.

flowering Moth dendrobium Orchid in focus

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.

“Don’t be afraid to move them around if they haven’t flowered for over a year as a change will often kickstart the blooms again,” Sara explains.

Are Blue Dendrobium Orchids Natural?

Blue Dendrobium orchids are not natural, as orchids do not naturally produce true blue or black flowers.

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

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.

References

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