The bearded iris

I think the tall bearded iris is the most beautiful flower, and certainly one of the easiest perennials to grow.

Artists paint it more often than any other flower according to David Schmidt. He is the curator of the iris collection at the Royal Botanical Gardens in Burlington, Ontario.

On a recent Sunday I visited the collection along with, it seemed, several hundred other people. Artists had set up their easels in the pathways, and everywhere people were snapping pictures of the regal iris.

David Schmidt was there too - making notes about the collection. "I map out which areas need to be renovated, which group needs to be divided, and I love to follow the breeding trends."

The trend, as in so many other perennials, is toward bigger flowers and stronger stems. He showed me one called 'Bronze Bell'. It was the colour of a precious metal, and the flowers were huge. It was bred in 1955, and if you compared it to an iris bred in the 20's, the size difference was remarkable.

And those strong stems - it means tall bearded iris can stand up to some pretty heavy weather. I've photographed irises after thunderstorms and all day rains, and they still stand erect and prettier than ever with their petals glistening with water.

To grow them well, just don't be too nice to them. Don't over-improve the soil, don't fertilize, and don't water them. Tall bearded iris are minimalists. David Schmidt has even seen a forgotten heap of rhizomes come through the winter in perfect condition - ready to be planted and bloom again the following season.

What you must do with the bearded iris is site them in full sun, and make sure the rhizomes are not planted too deeply. The rhizome, which looks like a pale sweet potato, likes to have its back exposed to the sun. That means all you people with mulch mania must resist the temptation to cover over the base of the plant with wood chips.

At the Royal Botanical Gardens the irises are planted in extravagant abundance, there are over 600 cultivars. It's an out of body experience to be there when they are at their peak of bloom, which can be anywhere in the first three weeks of June. In addition to the luminous colours in every rainbow shade, there is the fragrance. It is subtle, fresh, and cleansing to the senses.

In the home garden, tall bearded irises mix well with other perennials. Play off their severe, sword-shaped foliage, by planting something blowsy nearby.

Catmint (Nepeta x fassenii) is an excellent companion. It likes the same growing conditions, has violet-purple flowers and gray foliage, and will rebloom if cut back hard after its first flush of flowers. Other plants that will mix well with bearded iris are peonies, campanulas and columbine.

Not all bearded irises are tall. They are actually divided into six groups according to height and flower size. So you can move from tiny to tall, and enjoy flowering for over two weeks, since they bloom at slightly different times.

If you aren't already in love with the tall beardeds, let yourself go and plant a few. Then you might expand your tastes to include the Siberian iris. And once you see a Japanese iris (Iris ensata) you'll be preparing special beds for them in moist, acidic soil. There are also reblooming iris, which put on a second show in autumn.

Next thing you know, you'll be joining the iris society, going to iris auctions, and taking up painting.