Arresting aroma of orchid

Orchids come in such fragrant varieties that it’s easy to see why they’re so popular.
Orchids come in such fragrant varieties that it’s easy to see why they’re so popular.

Ask half a dozen people to name their favourite fragrant plant and you'll get half a dozen different answers.

Most probably won't mention orchids, but many of these exotic plants are scented. Some exceptionally so, and some vary throughout the day depending on the temperature and amount of sunlight they receive.

There are some that only exude their scent at night, like the pure white lady- of-the-night orchid, Brassovola nodosa. This small species has a divine citrus-gardenia like fragrance that begins in the early evening to coincide with its natural pollinator, a nocturnal moth.

Brassovolas are related to cattleyas, of which most are also scented, some intensely so. Cattleyas are showier, their blooms larger, and they're more commonly available in New Zealand. One of the most fragrant species is Cattleya walkeriana. If you're after a top scent, look for hybrids that have this species in their parentage.

Cattleyas should be grown indoors in bright light. Just a small amount of direct sunlight early morning or late afternoon is OK, but more sunlight than that and you'll fry them.

Many orchids in the oncidiinae subtribe are scented, in particular the oncidiums. I have oncidium 'Sharry Baby', whose white-tipped, cherry red blooms have a chocolate scent. Each flower spike lasts six to eight weeks, and the plant blooms sporadically throughout the year.

"These are coming into spike at the nursery now," says Cathy Hine from Tuckers Orchids in Auckland, "and will start flowering towards the end of the month. The perfume comes from the species Oncidium ornithorhynchum. This is a small spray type pink oncidium and has a very strong sweet perfume."

Following on from 'Sharry Baby' are the oncidium 'Twinkle' type orchids and their various hybrids. Their flowers are multicoloured, with varying combinations of yellows, reds, pinks and white. Their perfume can be described as smelling like candy, icing or chocolate.

Also beautifully perfumed are oncidium 'Tsiku Marguerite' and 'Gold Dust', which spike and flower a little later on. The former has cream to apricot blooms with a bright gold crest on the lip, the latter golden flowers with a bright orange crest.

"Oncidium 'Ruth's Rainbow' (x Onc sphacetante) is another popular hybrid that can flower throughout the year," Cathy says. "It has tall branched spikes either in gold [following the Onc sphacetante parent] or pink [from the ornithorhynchum parent]."

It may also have spots or streaks.

Oncidiums like an average night-time temperature of around 12 degrees Celsius, and humidity about 60 per cent in the immediate vicinity of the plant, as well as good air circulation or ventilation without there being cold draughts. Grow indoors or in a greenhouse for warmth.

There are other scented orchids to consider.

"There are some breeding lines in the cymbidiums that are scented - predominately if Cymbidium tracyanum or Cymbidium mastersii are involved," Cathy says. "As well, Osmoglossum pulchellum is a popular orchid that has a very sweet scent like lily of the valley and looks a little like it too, with its pure white upside down flowers. And many of the miltonopsis hybrids also have a beautiful citrusy perfume, usually from the Miltonopsis roezlii parent.

"There are even a few phalaenopsis [moth orchid] with scent, mostly having Phalaenopsis violacea, Phalaenopsis schilleriana or Phalaenopsis amabilis in the parentage."

But one of the most beautifully scented are those from the zygopetalum family. Their sweet, slightly musky perfume permeates the house for many weeks.

"The species Zygopetalum intermedium, Zygopetalum mackayi, Zygopetalum crinitum and Zygopetalum maxillaire are all scented," says Cathy, "and in the backgrounds of many of the modern hybrids usually imparting their scent as a major characteristic."

Zygopetalum like a fairly bright light, but not full sun or their leaves will burn. They are at their happiest with a night- time temperatures around 12C to 15C. Water when the potting mix has dried out, maybe once a week in winter and two to three times in summer, and feed fortnightly. Avoid watering the leaves or spots may appear. Repot, using an orchid mix, every couple of years.

Our Aussie cousins have come to the party too with fragrance.

"Many of the Australian dendrobiums are scented," says Cathy, "particularly those closely related to Dendrobium kingianum and Dendrobium speciosum. One small Dendrobium kingianum plant can scent a whole large room on a warm day. The scent can get a bit diluted and not as strong in the very complex hybrids."

Most Australian dendrobiums grow best in cool to intermediate temperatures, between 5C and 25C, although Dendrobium lawesii and Dendrobium speciosum and its hybrids like it a little warmer.

I grow my Dendrobium kingianum outdoors in a partially shaded spot. I don't actually feed or water it , but its small lipstick pink flowers still appear in spring year after year and continue blooming for two to three months. You can grow these orchids in pots, or mount them on tree trunks or fences.

Either way, there's a good chance wherever you are, you can grow a scented orchid.

The Southland Times