September is all about orchids

Orchids are one of the largest families of plants on Earth, second only to Asteraceaes; the group of flowers that include daisies and sunflowers. This incredibly diverse family of flowers includes around 25,000 species, which can be found on every continent on the planet, except Antarctica. From rainforests to mountain tops, orchids are found pretty much wherever plants can grow. There are even species that spend most of their life underground.

On top of the vast variety of locations they are found in worldwide, they can also be found growing on multiple different surfaces: attached to trees, on top of rocks or in the soil, and come in all shapes, sizes, colours. This, and the hybridisation by humans that commenced in the late 19th century, all contribute to creating the stunning, diverse and iconic family of plants that are the Orchidaceae.

Orchid growers in the late 19th century, who cultivatated and hybridised different species, had to be very wealthy to pursue their passion. This was because of the cost of finding, transporting and growing the wide variety of species in glass houses.

Now, thanks to modern developments, anyone can afford to grow orchids because they are readily available and many can be grown outdoors or indoors. Although there are still orchids that are sold for thousands of dollars, such as the Shenzhen Nongke Orchid. Developed by research scientists and taking 8 years to grow, one of these plants was sold for £160,000 in 2005 ($280,000) making it one of the most expensive flowers ever sold.

One of the key things to remember when growing orchids is to know it well. To achieve best growing results, make sure you understand the natural growing conditions, such as temperature, rainfall and light levels. If growing conditions are very specific, it’s probably going to be harder to replicate those conditions at home.

Hybrids are the result of two different species being crossbred and are often easier to grow as they often have a wider range of suitable growing conditions. In the case of our plant of the month for September, the Sydney Rock Orchid (Dendrobium speciosum), both species and hybrids can be grown outdoors in the garden, planted in a rockery or mounted on a sunny location on a tree.

Most orchids die from over watering, which can rot the roots. If the orchid species comes from an area which varies in rainfall throughout the year, then be sure to reduce watering during winter.

Typically, orchids that originate from temperate, high altitude or tropical regions grow well in Sydney. Whereas orchids from cooler regions, such as Masdevillias and Draculas, may not tolerate the hot Sydney summers, and are better grown in southern regions of Australia or inside glasshouses. Consider growing varieties orchids that tolerate hot weather, such as Crucifix orchids, Sydney Rock Orchids, Pink Rock Orchids, Hyacinth Orchids and Slipper Orchids if you’re thinking to grow them in Sydney.

As a stunning addition to your botanic home collection, orchids can be bought in pretty much any flower shop or supermarket worldwide. Most orchids only flower once a year, so don’t throw your orchid away once it loses its flowers and goes dormant. With some care and attention, it can re-flower again next year.

We have a very wide selection of orchids growing in various climatic conditions. Some are grown out in the grounds of the gardens whilst others are grown in a variety of glasshouses, such as our warmer Latitude 23 glasshouses. We have over 1,300 individual orchid plants and more than 500 different species and hybrids.

The stunning Sydney Rock Orchid, Dendrobium speciosum, is our flower of the month for September and currently in bloom around the garden. You can find this species and others using the Garden Explorer online database.

The largest collection we have currently is in the rockery in the Garden’s Middle Precinct, near the Wollemi Roundabout and next to the Succulent Garden. The flower colour varies from near white to golden yellow and flowers are held on arching stems and are often pollinated by native stingless bees.

When looking for orchids around the garden, be sure to check high and low! We have an orchid called Dendrobium teretifolium growing high in a tree by our education centre. During non-flowering we call this the Rat's Tail Orchid and during flowering periods we call this the Bridal Veil Orchid, take a look at the picture below to see why. It was originally attached to the tree in 1988, and continues to flower 60 years later.