10 things you didn’t know about orchids

There’s so much more to orchids than the showy specimens in supermarkets. See them in a new light with these 10 fascinating orchid facts

Treasured for their elegant and exotic flowers, orchids have long symbolised wealth and mystery; combining strange beauty, surreal colours, dizzy perfumes and bizarre biology in one vastly varied group of plants.

Orchid obsession reached heady heights in the 1800s, when collectors from across Britain and Europe raided the rainforest to bring back thousands of exotic specimens – rare beauties from faraway lands. Meanwhile, the UK boasts over 50 native orchid species of its own; many equally stunning as the exotics, yet hard to envisage as the cousins of the Phalaenopsis lined up on supermarket shelves.

The days of ‘orchidelirium’ may be over, but orchids have only become more fascinating as we discover more about their unique biology. In celebration of the opening of the brand new Orchid House at RHS Garden Wisley, along with the release of the first ever The Orchid Review yearbook, we’ve opened a window into their mysterious world through these 10 fascinating orchid facts.

Tropical Cymbidium orchids
British native common spotted orchid
1. Orchids are the world’s second largest flowering plant family

There are around 28,000 known species of orchid. This makes the orchid family second only to the daisy family, Asteraceae, in number of known species. It is thought that there could be many rainforest species yet to be discovered.

Orchids are also highly promiscuous, readily hybridising with each other to create novel plants. Though there are 28,000 accepted species, there are a further 192,000 different hybrids listed in the International Orchid Register.

2. Orchids grow on every continent except Antarctica

The success of orchids is in part due to their versatility. They grow almost everywhere: only Antarctica, some desert countries, and a handful of very isolated islands don’t have any native orchid species. They have diversified to grow in a huge variety of habitats, from arctic tundra to tropical rainforest, and from swamps to mountaintops and desert-like environments.

3. The world’s only underground flowers belong to an orchid

Orchids can grow on trees (epiphytic), on rocks (lithophytic) or even, uniquely among plants, entirely underground. Three of the four critically endangered Australian underground orchids (Rhizanthella) complete their entire lifecycle underground, including flowering. How they are pollinated remains mysterious, apart from in the case of the western underground orchid Rhizanthella gardneri, which is the only plant known to be pollinated by termites.

4. Orchids have the smallest seeds of any plant

Unlike most seeds, orchid seeds contain no food store. This means the seeds are the size of dust, and rely on fungi to germinate, which they parasitise to obtain nutrients for energy. One orchid seedpod can contain up to 3 million seeds.

5. Orchid flowers are upside down

Most orchids have a lower petal that is larger or more complex than the others. This is called the lip, and is specialised for attracting pollinators; acting as a landing stage once they reach the flowers. However, when the flower is in bud, the lip is on the upper side of the flower. As the flower opens, the flower stalk rotates through 180 degrees so that the lip is now on the lower side, giving a ‘twist to open’ effect. All orchids do this, except for a handful that have lost this trait during evolution.

6. Many orchids have aerial roots that can photosynthesise

Around 70% of orchids are epiphytic, growing on the trunks and branches of trees. Having no contact with the ground, they must absorb all the moisture they need from the air. The roots, which reach into the air, have adapted a spongy coating called velamen that allows them to absorb atmospheric moisture and rain.

These roots are usually green and can photosynthesise. Some orchids, such as Taeniophyllum species, have capitalised on this ability and have been able to do away with leaves altogether, carrying out all of their photosynthesis through the roots.

Unable to take up nutrients from the soil, epiphytic orchids must use other methods to obtain the nutrients they need to grow. Some epiphytic orchids have specialised roots that grow upwards to form a basket-like structure that collects leaf litter, which breaks down to release nutrients that can be absorbed by the plant.

Aerial roots on Phalaenopsis
Lady’s slipper orchids are closely guarded
7. One of the UK’s rarest wild orchids has its own security cameras

Several of the rarest wildflowers in the UK are orchids, such as the ghost orchid (which lives underground except to flower, may only flower once in 10 years, and hasn’t been seen since 2009), the fen orchid, and the lady’s slipper orchid.

The lady’s slipper orchid (Cypripedium calceolus) was once widespread across northern England, but was wiped out by a combination of habitat loss and a Victorian craze for orchid-hunting. By 1917 it was thought to be extinct, but in 1930, a single colony was rediscovered in a remote corner of the Yorkshire Dales.

A small group of guardians managed to keep the orchid secret from collectors for almost 40 years before a dedicated committee was set up in 1971 to protect the orchid’s interests. To this day, the site’s location remains a closely guarded secret, and the colony is under the surveillance of cameras throughout the year and monitored by wardens during the spring and summer months.

A reintroduction programme has now established colonies of lady’s slipper orchid at 10 sites in the UK using seedlings bred from the surviving wild plants.

8. Orchids can be masters of deception

While many flowers offer a nectar reward to entice pollinators, some orchids have evolved an altogether sneakier tactic. The British native bee orchid (Ophrys apifera) has furry flowers that mimic a bee, with the aim of luring in an unsuspecting male bee, which then attempts to mate with the flower and thereby pollinates it. This is known as pseudocopulation, and was discovered by naturalist Edith Coleman (1874–1951), solving a mystery that had puzzled Darwin. This strategy saves the plant energy in producing nectar, and the bee receives no reward for his efforts.

Bee orchids trick bees into mating with them
Vanilla comes from the vanilla orchid
9. Vanilla comes from an orchid

Vanilla is made from the seedpods of the vanilla orchid, Vanilla planifolia. This is the only orchid that is grown as a commercial crop. Around half of the world’s vanilla crop is grown in Madagascar.

10. Orchid showing is big business

Is orchidelirium still alive and kicking? Some might think so, given the rewards for presenting a prime specimen at top shows across the world. At the Japanese Grand Prix International Orchid and Flower Show, a highlight of the orchid enthusiast’s calendar, the winning Grand Champion orchid earns its owner a Mercedes along with nearly £15,000. Not too shabby!

The new Orchid House, located within the main glasshouse at RHS Garden Wisley, opened on 12 July. It showcases the best of Wisley’s collection of over 3000 orchids – a fantastic opportunity to get up close and personal to these diverse and mysterious plants.

In an RHS first, The Orchid Review yearbook is now available to pre-order from Summerfield Books. Providing cultivation advice, showcasing orchid collections and profiling orchids you will long to grow, as well as examining wild orchids in the field, it’s a must-have for all orchid enthusiasts.

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Essential reading for orchid lovers

The Orchid Review yearbook

The Orchid Review yearbook is now available to pre-order from Summerfield Books. Click here to find out more

The Orchid Review yearbook

The Glasshouse at RHS Wisley

Top tips for growing orchids at home

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