In Love with Japanese Irises

Japanese irises somewhat resemble other irises, but their blooms are wider and bigger, adding dramatic impact to any garden.

John Coble and Bob Bauer, owners of Ensata Gardens near Galesburg, Michigan, have been growing Japanese irises since 1985. "Most gardeners don't know about Japanese irises," says John. "Those who see them for the first time are amazed."

Here are John and Bob's tips to help you select and grow Japanese irises.

Pictured: 'Satozakura'

Ensata Gardens

You can tell a Japanese iris from the other members of the iris family by its narrow, sword-shape leaves, which can stretch 3-4 feet, and by its pointed flower bud. The delicate falls (petals) of a Japanese iris come in hues of purple, white, blue, pink and red-violet, and flap open 6-8 inches wide.

Pictured, from left: 'Angel Mountain', 'Eileen's Dream', 'Tea Ceremony'

Not only are Japanese irises beautiful to look at, but given the right conditions, they do well in the Midwest, says grower John Coble.

Japanese irises take some care, but they're not terribly high-maintenance. They bloom best in full sun, in well-drained soil that's watered well and mulched 2-3 inches deep. They should be divided every three or four years. Most varieties are hardy to Zone 4.

Pictured: 'Popular Acclaim'

Japaneses irises need 1-2 inches of water a week. 

Pictured: 'Crown Imperial'

Because irises set buds in the fall, next year's blooms depend on how well you treat the plants this year. Fertilize plants immediately after blooming is finished, which is in late June or early July.

Pictured: 'Tideline'

Blossoms last about three days in the garden or two days in a vase. If you plant early-, mid- and late-season varieties, you should have blooms for almost four weeks.

Try yellow coreopsis varieties as companions for Japanese irises because they bloom at the same time in a pleasing color combination.

Pictured, clockwise from top left: 'Silverband', 'Rosy Sunrise', 'Crown Imperial', 'Eileen's Dream', 'Tropical Storm'

For a truly Midwestern selection, consider the purple 'Kalamazoo' (in foreground in the photo). Hybridized by a Michigan man, Art Hazzard, it was introduced in 1996 and won the Payne Medal, a top award from the Society for Japanese Irises.

Singles have three falls (large hanging petals). Each fall has a triangular yellow "signal" in the center of the flower and three "styles" (small, upright petals) in the center.

Doubles grow with six falls, each with yellow signals, and three, four or six very prominent styles. The color contrast, number or form of the petals and styles can make one bloom appear merely pretty and the next one look spectacular. Pictured is 'Crested Surf', a double with six petals.

Multi-petals grow with more than six petals, usually nine to 12, each with signals and multiple styles.

Most Japanese iris come in solid colors, usually with contrasting styles; some have veins of another color on their falls. If you really want to know the lingo, "rays" are white veins twice as wide as other veins. 'Izu No Umi', at left, is a three-fall single Japanese iris that has white rays on a blue background.

Height is almost impossible to predict, because so much depends on the growing conditions in your garden. The average height is 32-38 inches in normal soil, with average moisture. In excellent conditions--rich soil, with lots of organic material and perfect watering practices--irises can grow 40-50 inches tall.

Flower size averages 6 inches in diameter, but better growing conditions can cause 7- or 8-inch-wide blooms.

Pictured: 'Raspberry Candy'

Want to get some of these lovelies for your garden? Ensata Gardens ships plants around the world (some of their biggest customers are in Japan and Russia) from April to mid-June, and from August through mid-October, when the plants aren't blooming. Ensata Gardens grows nearly 500 cultivars of Japanese irises—including two dozen they hybridized. About 200 are available through their catalog and website. They also sell Siberian irises, daylilies and hostas.

Pictured: 'Electric Rays'