The mighty iris

Rob Zimmer
It is peak bloom time for tall bearded irises in Wisconsin. Enjoy their spectacular colors and fragrance!

The peak of iris season is upon us and across Wisconsin, iris gardeners rejoice in the beauty, fragrance and joy of these spectacular late spring blooms.

Tall bearded iris peak in late May and early June, while shorter, bulbous and dwarf bearded irises begin to bloom as early as March, depending on weather, lasting into the early part of June. Other iris varieties, such as Siberian iris and Japanese iris, bloom later in the summer. Combining all of these varieties will help create an ongoing iris display from late March or April all the way through July.

As an added bonus, there are a number of tall bearded iris that are reliable re-bloomers that will put on a secondary display in August, September, even into October and November if we have a warm autumn.

Irises bloom in all colors of the rainbow, from pure white to jet black. This beauty is named Jurassic Park.

Iris explosion

It is the tall bearded irises that put on their spectacular display now, dancing in the warm breezes of late spring as they unfurl to display massive blooms in every color of the rainbow.

There are irises that bloom in pristine white, as well as true, jet black. In between, irises can be found in every color of the rainbow. Some of the more popular are those that bloom in shades of rich, deep purple, blue, red, pink, orange and yellow.

There are also a number of incredibly dramatic irises in bold colors, as well as streaked irises that are marbled or striped in pattern.

Peak bloom season

One of the most incredible places in Wisconsin to view tall bearded iris in peak bloom is at Willow Creek Farms, located on State Highway 22 just east of Wautoma. Here, you will discover a breathtaking display of 150,000 tall bearded iris in simultaneous bloom during the first few weeks in June.

Stroll among acres of fields planted with thousands upon thousands of tall bearded iris in every color imaginable. The sweet fragrance of iris in bloom drifts through the air as you enjoy the beautiful showcase display.

Be sure to plant your iris rhizomes properly to enjoy season after season of colorful, dramatic bloom.

Iris care

Growing tall bearded irises is easy, as well as rewarding, provided you follow a few simple rules. Irises grow best in full sun. They also prefer well-drained soil. Heavy moisture will tend to rot away the plants.

Tall bearded iris grow from large, fleshy rhizomes. In ideal conditions, they spread quickly, intertwining to form a dense mat. In order to keep bloom vigorous, these intertwined rhizomes must be split, or divided, every two or three years and replanted.

A common mistake many gardeners make when growing bearded iris is planting these rhizomes too deeply or in soil that is too rich. The rhizomes should be planted horizontally with about 1/3 of the fleshy, potato like growth above the soil line. This allows the iris rhizome to bake under the summer sun, which is just what the plant wants to do.

Planting the rhizomes too deep will result in lush, green growth, but very little bloom.

Irises are susceptible to iris borer, a type of large caterpillar that feeds upon the fleshy root. This results in mushy roots and weak leaves that pull easily from the plant.

Iris borer is generally not fatal to the plant, as long as it is caught early and treated appropriately. The plant needs to be dug and the rotted portion scooped out with a spoon. Soak the rhizome in bleach water and replant.

The best way to avoid this pest is to keep iris beds clean of debris in late summer and fall when the moths are laying eggs.

Find Rob Zimmer online at On Facebook at Listen to Outdoors with Rob Zimmer, Saturday mornings, 7 - 8 AM on WHBY.