Swamp Isotome

Swamp Isotome (Isotoma fluviatilis subsp. australis)


Swamp Isotome
Small enough to look like ordinary lawn weeds when glimpsed from a standing position, these native Australian flowers are quite interesting when viewed close-up.


According to the field guides I consulted, the Swamp Isotome grows seasonally in moist depressions.  I didn’t really think we had any moist depressions as the soil is very sandy and doesn’t hold water for long.  When I think about it, the seepage from the dam probably flows beneath the spot they were growing.  This grassy area is also where the Ivy Leaf  Violets were growing.

Initially I thought the Swamp Isotome was an exotic weed.  I almost didn’t bother to photograph it.  However, my habit is to photograph anything in flower so I can record both exotics and native plants, so I took this shot in haste, with the intention of  identifying it.  The photograph was taken in November, but I really can’t say how long the flowers lasted.  My impression was that they were contained to a small area, and there were not very many of them.  I look forward to photographing them again in November  this year, to reveal the details of the flower more fully.

Swamp Isotomes are matting plants and the flowers can range in colour from mauve to blue.


4 thoughts on “Swamp Isotome (Isotoma fluviatilis subsp. australis)

  1. A single small plant of Isotoma fluviatilis spp. australia was recently found growing among thick Kikuyu and Couch grass on Cheltenham Golf Course. It is still flowering now (late December) but the flowers are fading and losing their lovely mauve markings. They seem to stay open for several days. I’m guessing it was once widespread in Bayside Melbourne, before the wetlands were drained and suburbs sprouted in their place. Now we have just one plant left. I’m hoping to grow it and pass it on to our indigenous community nursery. I see from records of the local bushland volunteers we once also had Lobelia pedunculata, which seems somewhat similar. Must go out and try to find it…

    1. Thanks Rob, that’s really interesting. I read Tim Flannery’s “The Birth of Melbourne” which contains very detailed descriptions of the natural environment all around the Bay – so many beautiful things have been forgotten or lost. Anyway, I am happy you found the single plant and I wish you well in growing it. I must say, I haven’t seen a lot them here either. Every now and again they seem to pop up, but never in large quantities. Even this year with all of the Spring rain I don’t think we had any. Lisa

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