Monday 23 October 2017

Diarmuid Gavin: Indoor delights - the beautiful and hardy orchid

A flower as beautiful and hardy as the orchid deserves more than a lapel to showcase its diversity

The Phalaenopsis or Moth orchid
The Phalaenopsis or Moth orchid
A Cattleya orchid flower
A species of Odontoglossum

One of the gardening delights of the post-Christmas season is that the pot plants we grew, purchased, or were gifted, continue (with a little care) to delight us through the winter months. While the wet, windy or frosty weather swirls around outside, we can still enjoy some of nature's colourful wonders with indoor flowering plants.

My seasonal hyacinths, purchased as sprouted potted bulbs a week prior to December 25, are still flowering away happily and the winter cherry plant (Solanum capsicastrum) still is graced by a hoard of vibrant orange berries.

But the flowering plant which intrigues the most, both for its drama and durability, is the orchid - a species that has been coveted since the moment of its discovery.

The orchid family is one of the largest family of flowering plants in the world - it is estimated there are over 25,000 different species, some as small as a penny, some weighing up to a tonne. They can be found in all climates across the world, except for Antarctica, and have the ability to grow on rocks or clinging on to trees.

A craze in the 19th century for collection in the wild resulted in near extinction of some species - the Lady's Slipper orchid was down to just one surviving plant in the first half of the 20th century, but it has been successfully propagated and reintroduced around these islands.

Today's scientific progress in plant cultivation techniques has made many varieties of orchids readily available. Some, such as the ones sold in the supermarkets as gifts for loved ones, are easy enough to grow.

However if you're about to become an orchid connoisseur, you will require some knowledge, as orchids from different altitudes should be grown at different temperatures. An understanding of what type of orchid you have will enable you to provide the best conditions.

We do have beautiful wild orchids in Ireland, but in mid-winter I'm going to concentrate on those which provide indoor delights.

The most commonly seen orchid is the Phalaenopsis or Moth orchid (pictured main) - these are the ones found in supermarkets and DIY stores as well as petrol stations and garden centres. This a warm orchid from the tropics, so it needs a comfortable temperature during the day, and you must make sure it doesn't get too cold at night - not below 18˚C.

A Cattleya orchid flower

Intermediate orchids can take it a little cooler at night, around 13-15˚C. This group includes Cattleya (above), also sometimes known as the Corsage orchid, as it is a popular choice in corsages and wedding bouquets because of its fragrant, showy flowers.

Finally there are the cool orchids like the Odontoglossums (below) which come from high mountain areas and prefer it cooler, so a porch or conservatory is ideal.

A species of Odontoglossum

Good light is important, but none of them like to be scorched by sun, so with south-facing windows you will need to pull the blind to filter the light.

At home ours all end up on a north-facing window by the kitchen sink where they benefit from the moist air circulating around the sink and the occasional steam cloud generated by the kettle. This combination seems to encourage bright blooms for months on end.

However, they don't like to be overwatered - once a week is fine, and make sure that they're not sitting in water or their roots will rot. Special orchid compost allows the water to drain freely through and should dry out completely between waterings. If your water is hard, rain water would be better. I like to use slightly warm water, imagining I'm a replicating a tropical shower. The leaves and flowers will also appreciate a light misting.

Every so often, it pays to gently clean the leaves - dust on leaves can block out light and it also gives you a chance to inspect and remove any bugs such as spider mites, aphids or mealy bugs before they build up. And remember to feed with specialist orchid feed every now and again - they won't need loads and don't overdo it as this will do more harm than good.

Every two years is a good rule of thumb for repotting as the orchid compost starts to decompose - pot up with fresh compost, taking care not to bury aerial roots sticking out on top. With Moth orchids, usually the same size pot is fine, with others such as Cymbidiums you need to allow for expansion.

If you've ever opened a vanilla pod to scrape the seeds out, you'll know how tiny and difficult to handle orchid seeds are, because of course the vanilla plant is an orchid. So if you want to propagate, vegetatively is the best way, either by cuttings or division. Cattleyas and Cymbidiums can be divided after flowering in spring, while small plantlets can be removed from the Moth orchid and repotted individually.

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