Irises are Lovely on Land, But Perfect for the Pond

Lovely on Land, But Perfect for the Pond by Carol Wallace

When we built our first pond (they DO get addictive!) I was surprised to see Iris listed among the possible plants I could stock it with. I was accustomed to bearded iris that would rot if it so much as rained for three days straight. I couldn’t imagine growing an iris in water. And so I didn’t.

Later, at various plant sales and end of the year specials I picked up a smattering of Siberian and Japanese iris – I have this thing for rescuing sick plants and seeing if I can bring them back to life. The Japanese iris did not look promising – so I stuck it on a brick on a shallow shelf in the pond. To my surprise, it loved it there. Cautiously I sneaked in a division of my Iris laevigata– and it was happy too.

Later I expanded my repertoire to include others – Louisiana iris, Iris versicolor (blue flag), Iris pseudacorus and Siberian iris. And sure enough, the books were right – these plants not only will grow in water as well as in my garden – they thrive there.

Japanese iris aren’t really pond plants so much as semi-bog plants – they don’t like to be wet all the time, but they do appreciate moist soil. If you have a natural pond these are perfect plants for growing at the edge. Any of the other iris I named will also do well here – as well as in ordinary garden soil. But the others will also actually grow in water.

My favorite is I. laevigata ‘Variegata’ – mainly because I’m a sucker for variegated foliage. This plant has leaves striped vertically in green and white; mine blooms in a lavender blue. They also come in white and can get up to 2’ tall. Many books claim these are true bog plants – but mine are thriving on a small shelf in the pond about 6" below the water level.

I also loved my Louisiana hybrids. I read that they will grow best in a bog or pond, so they were one of the first plants I ordered when we built our own bog. These lovely plants come in a multitude of colors from the pure white ‘C’est Magnifique’ to the nearly black ‘Black Gamecock’ with shades of pink, yellow and lavender in between. I was amazed that an iris from Louisiana would do well here in my zone 6 garden – but it did beautifully until the Iris pseudacorus smothered it. Ah well – it was lovely while it lasted. I may try again, but this time right in the pond – they will grow happily in water up to a foot deep.

And the iris pseudacorus? I’d heard that it was invasive. I should have known that it was invasive when friends from out of town came toting a clump of it about the size of a small baby blanket. I planted it just outside of the bog, where it would catch some of the runoff without getting too wet – I thought maybe that would keep it in check. But it was sneakier than I thought.

Although the bog liner kept Iris pseudacorus from invading by its roots, the thing went to seed. It planted seed in the bog. It planted seed between the pond liner and the rocks surrounding the pond. It planted them in the lotus pots. I saw iris coming up in places where I knew I’d never planted them. All yellow, all about 5’ tall. They looked cheerful – and well they might, having successfully conquered the Louisianas and taken over their territory. And while they are lovely, I have no intention of playing sentry to these guys. Anything that blooms now gets immediately deadheaded. And when they are done flowering this year they are all leaving. However, if you have a lot of moist land to fill and love yellow you might want to give these a (cautious) try.

One saving grace that this iris has is that if you plant it in a relatively small pot (in isolation – don’t let it near other pots!) it will soon grow right out of that pot and keep on going. While that may not seem like a saving grace, the roots of the liberated portion of the plant are great as a natural water filter. So maybe I won’t get rid of all of mine.

A more well-behaved and quite lovely plant is the blue flag iris, Iris versicolor. I have one lovely clump of these blooming in quite dry land surrounding my small pond (which, being concrete, does not have a moist pondside area.) I have another pot of it growing in the pond – it is somewhat vigorous and will plant itself in other pots if not watched – but I haven’t had any difficulty controlling it.

The blooms are absolutely lovely – mine are a cloudlike blue which serendipitously exactly matches the flowers of the Iris laevigata growing next to it. Mine on dry land grows only about 18" tall – but the one in my large pond grows stupendously. I put a small pot of it in last fall which immediately got knocked to the very depths of the pond and forgotten. I saw something growing at the pond’s center this spring and vaguely hoped it was a lotus that had suffered a similar fate (the dog decided to go for an unscheduled swim) – but to my surprise, the tentative growth turned out to be Iris versicolor. I assumed all I would see was leaf tips – but it has been blooming merrily for the past 10 days. Obviously these babies can take deeper water than the books recommend. Normally it can grow up to 3’ tall – but this one has to have reached 5 feet to get above the water’s surface and bloom.

Now I’ll be honest and admit that I haven’t tried Siberian iris in the actual pond, although they do seem to thrive on boggy conditions. The best looking clump I have right now, though, is growing in dry-ish soil in my raised bed garden. However, they are recommended as pond plants and as soon as mine are done blooming I am going to divide one of the clumps and give it a try. I love the grasslike foliage, the various shades of blue, purple and lavender that they bloom in - and the fact that they will grow in partial shade means that the end of my pond which gets shade from the apple tree will finally have something growing in it.

All of these iris are hardy from zones 4 through 9 – Siberian iris may even grow in zone 3. All I do with mine in fall is lower them to the bottom of the pond, which is deep enough to put them just below the frost line. (Bringing them up in spring can be cold work, but I bought my husband a wet suit and he says he enjoys it. Somehow, he never quite got around to it this year, though – which is how we discovered that Iris versicolor would get so nice and tall.)

They look nice as a single specimen, adding a vertical element to the numerous horizontally floating lily pads. But they also look sensational massed together for a fabulous late spring show – and the foliage lends a good, architectural note to the pond plantings all season long.

The funny thing is, I no longer grow any bearded iris – they were just too much trouble. But my iris repertoire has expanded vastly along with my ponds – and I expect it will keep on growing.

About the Author

Carol is a garden writer and college professor in northeast Pennsylvania. She manages the Gardening section of Suite 101.com, where she also writes the column Virtually Gardening.