Irises are great plants for the Maine landscape – a great plant for the casual gardener as well as for those who become obsessed by a single species.

The blooms can span from early spring for some of the dwarf-bearded irises to as late as early August for some of the Japanese irises, and blossoms range in color through purple, red, yellow, white, brown and many shades in between.

Additional Photos

The "Crimson Fireworks" iris is a stunning hybrid. Courtesy Jeff Dunlop

I spent a good part of June 8 at the 53rd annual iris show held by the Maine Iris Society at Auburn Middle School, and the striking blooms on display impressed me.

Peter Young of Buckfield, a past president of the Maine Iris Society, said irises are first divided into two categories – bearded and beardless. The bearded varieties are further divided into miniature dwarf, standard dwarf, intermediate, miniature tall, border and tall bearded irises. The beardless varieties are Siberian, Japanese and species irises.

Jeff Dunlop of Windham said that in the Iris genus, there are more than 200 different species. And in those different species, there are thousands of varieties.

In a minor coincidence, when we got home from the Iris show, we had an email from White Flower Farm promoting the company’s irises, and the company offered 40 tall bearded irises and 14 reblooming irises just in that promotion.

While most members of the Iris Society grow their irises in rows or blocks, they also work well as part of mixed perennial gardens. They need at least six hours of direct sun each day, and well-drained soil.

Sharon Whitney, who specializes in Japanese irises, hybridizing and selling them at Eartheart Gardens (eartheartgardens.com) in Harpswell, said that Japanese irises tend to be more fussy than Siberian or bearded irises, needing both a richer soil and more water. She will be holding open houses through the end of July on Sunday and Monday afternoons.

Dunlop, who works with Dean Cole of Gorham hybridizing Siberian irises, said Siberians work especially well in a landscape situation.

“They have good foliage that stands upright all year, even after they bloom, so they look good in the garden,” he said.

Dunlop and Whitney are carrying on the work of Currier McEwen, a renowned hybridizer of Japanese and Siberian irises in Harpswell.

McEwen hybridized and introduced to market more than 100 irises in his iris career, which began in Harpswell after he retired from his career in medicine. He died at age 101 in 2003.

Dunlop and Cole do the Siberians, while Whitney grows mostly Japanese iris.

Dunlop was excited about one of his hybrids, “Crimson Fireworks,” that was competing in the seedlings division of the iris show.

Bringing an iris to market is a long process. You hand-pollinate the irises when they are in bloom, then wait for seeds to develop in the pods. After you plant the seed, it takes at least two but usually three years for the plant to flower. And you might want to check out the flowers for several years before deciding to take it to market.

Any irises that Dunlop and Cole decide to bring to market, they sell through Fieldstone Gardens (fieldstonegardens.com) in Vassalboro.

All plants brought to market are created from the first selected plant, so the plant will have to be grown and divided for about 10 years for a company to have enough of the irises to sell.

Dunlop and Whitney said they are looking for a lot of different things when hybridizing plants. Part of it is to create new colors and shapes. They also aim to produce hardier plants, as well as plants that extend the blooming season.

Another strong attribute for irises is to have multiple branches, because each branch will bloom at a different time, extending the bloom time.

All irises have to be divided occasionally to stay healthy. Young said bearded irises should be divided about every four years, Dunlop said Siberian irises can go four to six years, while Whitney said Japanese irises should be divided every three to five years, but it varies.

“Some grow a lot faster than others,” she said, so you should decide based on each plant.

Irises can be divided in two basic ways, Young said. Some people dig up the whole plant, divide it as much as they want with their hands or a knife, and then put part of it back. That is the method Nancy and I use. Others prefer to leave the main plant in the ground and cut or pry part of it away from the main plant, which is neater and maybe less shocking to the main plant, but takes time.

Young, Dunlop and Whitney are accomplished iris growers, but the Maine Iris Society is a big help for beginners as well.

Judy Alderman of Delray Beach, Fla., discovered irises when she bought a seasonal home in Harrison. That home garden was just about bare, so she had a lot of space to fill, and discovered the Maine Iris Society when she started working on that garden.

“I just love irises because I can’t grow them in Florida,” she said. “They come in many colors, and they last a long time.”

She enters the design sections of the Maine Iris Show and has won some ribbons there, but has not won in the specimen classes.

The Maine Iris Society holds four major events each year. The show for early irises was held in Lewiston May 18; the June show is usually held in Auburn.

The Annual Iris Auction, open to the public, will be held at 1 p.m. July 20 at the Treworgy home and garden at 120 Flaggy Meadow Road, Gorham. As an aside, in 2005 when the Maine Sunday Telegram held a contest for best Maine gardens, the Treworgy garden was the winner.

In addition to irises, there will be daylilies and hosta for sale.

The Annual Late Summer Auction will be 7 p.m. Sept. 10 at the United Methodist Church, 439 Park Ave., Auburn.

For more information, go to irisgarden.org and click on the Maine Iris Society. The Maine Iris Society also has a Facebook page.

Tom Atwell has been writing the Maine Gardener column since 2004. He is a freelance writer gardening in Cape Elizabeth and can be contacted at 767-2297 or at:

tomatwell@me.com