PlantFiles: Wild Iris, Blue Flag
Iris setosa

my wild blue flag iris is so much better and more productive than the domesticated kind, which is smaller, and blooms quickly, than stops. I love this wild variety - please see my pix...

Living in North Florida, zone 8b, I have never seen an Iris setosa, but I have seen many of its natural children, Iris versicolor, which will grow as far down as the Coastal South of the US, so I am quite interested in this species.

Iris setosa is the least dependent on wet conditions and has one of the widest native distributions of all the iris. It grows from Eastern Siberia, to Japan, then over the Bering Strait to Alaska, and then skips the middle of Canada to show up again in Eastern Canada, and then into Maine in the mainland US. Sometimes this far Eastern Canadian and Maine type is called I. hookeri. In Alaska I. setosa is often very short, under one foot tall.

Iris setosa is also unusual in that the standards (the three upright petals) are so reduced in size as to seem absent, putting it in the iris series Tripetalae. (If you are interested at all in the classification of plants, a study of the intricate structure of Iris classification is fascinating.)

Iris setosa hybridizes readily, and is a "hybridizer's dream." It is often crossed with the Laevigata group, which is a grouping of Asian, North American and European wetland iris, often found in the wild in standing water. Iris virginica, a giant--often over six feet tall--very common Laevigata native iris of the Southeastern US, and also called the Great Blue Flag, is the other parent of Iris versicolor. How this giant native iris of the Southeast US and the very short native iris of the North came to naturally cross to produce the beautifully multicolored Iris versicolor is a story of evolution at work.

Botanists think that during the height of the last ice age Iris setosa was pushed so far South to escape the advancing glaciers that it actually moved into the territory of Iris virginica in the Southeastern US, and there the two wild species naturally crossed to produce their lovely children, Iris versicolor. As the glaciers retreated back North, so did Iris setosa, and the two parents again became separated, but their children, Iris versicolor, still flourish, thousands of years later, both in the wild and in our gardens.

Iris versicolor did inherit a full set of chromosomes from both of its parents, having a total of l08, which is the most chromosomes for any iris, and nearly approaches the record for any plant! Having this many chromosomes makes I. versicolor very variable and vigorous. It will grow well in a border and crosses with the Japanese irises, creating Versatas, and also crosses with Siberians. The iris world is indeed very complex!

Our Alaskan wild iris grow in meadows, bogs and long the edges of waterways. They can grow up to 2 feet tall and have swordlike leaves. The flowers grow on sturdy stocks and can be blue, purple, violet, and occasionally white. Wild Iris adapt well to the garden, but may need to be divided every few years.

Wild Iris may be started from stratified seed, but it takes years for them to develop in size. Division is the easiest and most expeditious method.