Louisiana iris

I do love all those spectacular, show-off blooms that strut their stuff for just a week or two, then disappear until the same time next year. Right now, it's Louisiana iris time. The whole glorious display will be over before November comes around, yet each time I see the "real things" in bloom I feel that same sense of magic that I felt the first time I saw these enormous bluey-purple dazzlers.

Each of these pond plants' blooms flowers like this for just a day or so, and then as it fades another comes up to replace it, then another, then another. It's as if it has its own rhythm section, its own conductor telling each bloom, showbiz-style, that "you're up on stage now, go for it."

Here's one of my three Louisiana iris pots. This one is filled with water, has goldfish swanning around inside rather beautifully, and there's a small, second pot inside this larger pot that holds the soil and the iris plants. The smaller pot sits on an unlovely stack of bricks, so that the water level is always about an inch or two below the top of the soil level. That means the roots are permanently in water, which is how they like it.

The only problem I have experienced with these plants is that they multiply like crazy! I can't keep on setting up water pots everywhere (as they are high-maintenance things) and so when it was apparent mid-year that the iris population was outgrowing its existing two water pots, I decided on a desperate move: I planted up some of the excess iris rhizomes into ordinary potting mix and set myself the task of keeping them well watered.

And they've thrived. So, here in Sydney's mild, humid, temperate climate I think you could classify Louisiana iris as a potential weed if they made it down to the riverbanks, which is their natural habitat.

They need so little encouragement to grow, they multiply like mad (my whole three-pot empire of the things started off as a single pot containing one baby plant back in 2009 — read about it here).

Apart from providing the water supplies that are so essential to them, all I give them is slow release fertiliser pellets. At first I was Mr Keen, buying slow-release pellets for azaleas and rhododendrons, which like the same kind of acid-soil conditions as Louisiana iris. Lately I've been giving them "All Purpose" slow release Oscmocote, and it seems to be working far too well as far as I am concerned.