Mostly the water is shallow, with a lot of leaf litter from
the huge Melaleuca leucodendron trees growing along the
western side of the drain. There are always plenty of seedlings
growing around the parent plants. The habitat is fairly shaded,
with morning sun only. Monochoria cyanea grow where there
are breaks in the shade and various Cyperus species as
well as grasses are found in the more shallow parts.
The other place I have collected it is Keatings Lagoon just
south of Cooktown. I was photographing the lagoon and plants
in April 2007 when I spotted a small lily in a few inches of
water at the base of a big Melaleuca. It was very shady
there. When I investigated I thought it was N. nouchali
and collected it. It was not in flower, but was a healthy plant.
This lagoon was almost full of tall Eleocharis sp,
but in the clear spots in full sun, N. immutabilis were
flowering. There were large Melaleuca trees around the
perimeter of the lagoon where the water was shallow, and probably
crocodiles in the lagoon so I dared not venture in.
The first ones I collected from around the airport about 10
years ago were difficult to grow and died within a short time.
I wondered if the water at that time was slightly brackish, and
that the plant resented being put straight into sweet water.
Other collectors also found them hard to cultivate at that time.
Since then I have collected them and grown them successfully.
I have had the Keatings Lagoon plant flower for me as well.