We buy orchids in flower, but all too often they’re the last flowers we see. How can we ensure that they bloom year after year? Plantsman Graham Rice offers some advice
There was a time when orchids were thought of as rare and exotic, only available from specialists and challenging to grow. Now, thanks to new advances in breeding and in laboratory propagation, you can buy them in flower in the supermarket, often at very reasonable prices, and grow them on the windowsill.
But they are still extraordinary plants, and deserve to be looked after so that they provide many years of gorgeous blooms.
How can I get my orchids to rebloom?
Start, of course, by growing the different types of orchids in the conditions they like best. You can find out more about growing a variety of orchids on the RHS website. Some orchids are difficult to coax into bloom more than once, especially if you’re growing them in the house. But there’s one easy trick that helps enormously: make sure that the temperature at night is lower than the day temperature.
It doesn't take much, but lowering the heat by 5ºC (10ºF), usually in autumn, will often kick plants into flowering. Moving them to a different room in the house may be all they need but it makes a huge difference to most of the orchids we grow in the home.
Also, choose types that are most likely to rebloom. Moth orchids, Phalaenopsis (see photo), are the easiest and come in a vast array of colours and patterns. But be careful when you’re dead-heading; never cut the tip of the flowering shoot off if it’s still green as you’ll be cutting off buds. And don't cut the spike right out, snip it 2.5cm (1in) above the second notch from the base; it will probably branch below the cut and make new flowers faster than growing a new spike from the base.
Another group that you can encourage to rebloom is the slipper orchids, Paphiopedilum (see photo, top), especially those with mottled leaves. These lovely plants, with their bold pouched flowers may only carry a single flower on each stem, but that flower may bloom for as long as four or five months. Dropping the temperature in autumn will encourage more flowers year after year.
Unusual and fragrant orchids
Another orchid that's especially easy to get to flower every year is Oncostele, sometimes known as Colmanara; look out for Wildcat which can flower two or three times a year in a variety of mahogany, red and yellow shades. When it’s happy it will bloom for two or three months, take a few months off, bloom again – and so on – all year round.
Finally, look out for elegant and fragrant cockleshell orchid, Prosthechea cochleata (syn. Encyclia cochleata, right). The flowering shoot keeps extending – unless you cut it off – and developing more flower buds so hold back with the scissors. This is also a neat and compact plant, so takes up little space.
But remember that one trick that works with so many orchids: ensure that the night temperature is 5ºC lower than during the day.
Then sit back and enjoy the flowers...