Dove orchids in bloom

My garden smells wonderful this morning – every single clump of dove orchids is in full bloom. Read about them at Dove Orchids and the verdict, Unreliable Orchids, if you don’t know them.

Now … is it going to rain in ten days’ time? or are they responding to the little bit of rain (about 10 mm on the 24th) we had a week ago? or neither, or both? Time will tell. Meanwhile, I will get into the garden and enjoy them.

 

Unreliable orchids

dove orchid
Dove orchid blooms and bud

I have written several times about dove orchids and their fabled ability to predict rain, trying to test whether the fable is true or false. I followed up this post in January 2015 with comments recording flowerings and rain, and they weren’t doing too badly. But then came the Wet (well, as much of a Wet as we seem likely to get) and they failed utterly.

The flowers in my photo appeared on Saturday the 12th in the first blossoming since Christmas, so our doves had totally ignored decent rainfall on the 3rd, 10th and 30th of January, the 1st and 9th of February and the 1st, 4th-5th-6th, 9th and 10th of March (stats are here, with a bit of digging – links to BoM data are once-only).

The rain we got on the night of Feb 8th (which shows up as Feb 9th in the records) was far greater than shown in the ‘Townsville’ statistics which come from the airport some distance away. Aplin’s Weir, our nearest weather station, recorded 91mm in 30 minutes, 143mm in an hour and 181mm within two hours; it was accompanied by serious thunder and lightning, too.

The orchids didn’t ‘predict’ any of these falls, nor (for the record) did they flower nine days after any of them, as the accepted science says they should have done. Even the thunderstorms didn’t prompt them to flower. If (and I’ve got to say it’s a big ‘if’) we get a lot of rain around the 21st, I will be grateful but I won’t be saying, ‘I expected it because the orchids flowered.’ They are beautiful but unreliable.

Dove orchids in flower

white orchids with yellow tongues
Dove orchids promising rain to come

We noticed that our dove orchids were in bud yesterday and this morning they were all in flower. I went out to take a photo for the blog and couldn’t work out why I was so disappointed with the result until I realised that I was missing the scent … silly, really, but quite unconscious.

I introduced these orchids at some length in November 2011 and won’t repeat all that information here but just say that they are a well-established exotic, Dendrobium crumenatum, and are generally thought to predict rain. My readers have been informally helping me test that theory via their comments to that post, and my summary of the results so far is that it’s beginning to look like we have two patterns:

  1. Flowers appear a few days before heavy rain.
  2. Flowers appear very soon after a thunderstorm breaks a dry spell.

Today’s flowering is our first this year and we haven’t had any thunderstorms recently, so they must be saying rain is on the way. Our weather forecasters agree, saying that there is a moderate chance of a cyclone forming off the northern coast in the next few days and a good chance of some heavy rain from that weather system whether it becomes a cyclone or not. All we can do is wait and see.

 

Spotted doves

pair of birds on branch
Spotted Doves, Streptopelia chinensis, high in our paperbark tree

I have been trying for about a year to note all the species of birds in our garden and I am still adding new ones to my list. I saw these two doves fly into the branches of our paperbark tree, only just within reach of my telephoto lens, yesterday. Slater’s Field Guide tells me they are Spotted Turtle-doves and that the species is introduced, not native, and is now a “common resident around cities and large towns … spreading into natural bushland”. The distribution map shows them east and south of the Great Dividing Range from about Cairns to Adelaide, but I don’t think they can (yet) be very common here.

This couple were sidling up to each other like these two amorous Peaceful Doves but they just preened for a while and flew off again. They are, incidentally, quite a lot larger than Peaceful Doves – Slater’s says 27-28cm compared to the Peaceful Doves’ 19-21cm.

Speaking of doves, the dove orchids just outside this room have flowered this morning. I knew without even looking, because I smelt them when I opened the window – a lovely smell but quite strong. These orchids are supposed to predict rain but I have just checked and the other two clumps are not at all interested in flowering. I guess we will just have to wait and see.

Dove Orchids

Local lore has it that the our common Dove Orchids flower ten days before rain. It is approximately correct on all points.

Just so we know what we’re talking about, here is the flower:

a spray of Dove orchids
Dove orchids

The flowers are quite small, about 5 cm across, but are abundant and have a lovely scent. Sometimes we walk into the garden, take a deep breath and realise the orchids are out before we see them. The flowers do only last for a couple of days, unfortunately, but they are very pretty for that time. Between flowerings, the plant is easily overlooked – a messy tangle of stems, roots and leaves, especially if it has been there for a while. The dull green leaves are 6 – 7 cm long and 2 – 2.5 cm wide.

messy orchid plant
The orchid after flowering. This one has been on its palm trunk for several years.

Now, about all those partial truths:

  • Dove orchids are not quite local. They are native to a broad area of southern Asia (from India, Malaysia, Indonesia and Vietnam to the Phillipines and China) but not, apparently, northern Australia. New Guinea and Christmas Island, yes; Australian mainland, no. But they are well established in gardens around Townsville, growing and propagating happily with no attention at all. If wouldn’t surprise me if they have gone feral along our tropical coast.
  • ‘Dove orchid’ is the only common name used for them locally, and it is quite appropriate because the buds are shaped like little white birds; some people see a resemblance between the open blossom and a dove in flight, too. But ‘Dove Orchid’ is used for a quite different flower in Central America and some sources call ours the ‘Pigeon Orchid’. The scientific name is unambiguous, of course: Dendrobium crumenatum.
  • How could a plant ‘know’ that it is going to rain? It can’t, of course. We thought for a long time that our orchids were responding to an increase in humidity but it turns out that flowering is triggered by a sudden drop in temperature (Orchids Wiki suggests ‘at least 5.5 C’ is needed) and all the flowers will open together nine days later, not ten, according to my sources. The temperature drop often precedes the onset of rain, so once again, a partial truth.

All of our dove orchids – four clumps of them in various trees and shrubs – flowered together last Friday. Let’s see if it pours rain tomorrow or Monday!

Friday 11 November: the results are …

Townsville got 3.8 mm of rain on Monday 7th, none at all in the week before that day and none in the following two days, according to the BoM stats.

The Monday was the tenth day after the orchids flowered, so it looks like local lore is vindicated. On the other hand, those rainfall figures are for the airport and we may not have had even that much of a shower – and 3.8 mm hardly qualifies as ‘rain’ anyway!

In the immortal words of the last paragraph of every scientific paper written in the last fifty years, ‘more research is required.’