Thursday, September 24, 2009

Donkey Orchids

Diuris sulphurea

Wouldn’t you love to have a crop of these little fellows coming up in your orchard every spring? My neighbour found them last year while she was mowing, and only just missed chopping their heads off! They are there again, in the same spot, this year.

They are such a good reason for keeping a rough lawn of native grasses. Alas, that pesky weed, kikuyu, would have destroyed many such colonies, which grow naturally in the snuffy red soil along the range.

(Click on photos for a closer look)
North of Toowoomba, this habitat is being rapidly overtaken by acreage gardens such as this one. I do hope the householders are noticing the terrestrial orchids where they occur. Too much mowing would have destroyed this patch’s flowers before they had time to open.

Colony-forming ground orchids like these grow from little tubers, and multiply each year. The tubers were once eaten by aborigines, whose diet was rather low in starch, so they valued even such a small contribution as these donkey orchids could provide. Early white settlers ate them too - but fortunately, nowadays, we have more reliable sources of calories, and don’t need to eat our beautiful native flowers!

There are many species of donkey orchids (also known as “doubletails”), but this species is one of the most common, and can be distinguished by the two brown spots on the upper “petal”.

While ground orchids are considered more difficult to grow than the epiphytes, the donkey orchids are among the easiest of them. Growing them does, however, involve looking after a pot - or a patch of ground - which has nothing to show for most of the year. (Growers rarely do grow terrestrial orchids in the ground, but it should be possible to reintroduce this species to our gardens where they once grew naturally.)
In spring, however, each tuber puts up a few small leaves, followed by a single spike of flowers. It is usual for growers to put a number of tubers in each pot, to make an attractive display.

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