Iris

Read and learn about the 7 main types of Iris below.

TYPES OF IRIS

Iris ensata
Japanese Iris

Unlike the Tall Bearded Iris, the beardless Japanese Iris has a flat bloom, narrower leaves, and smaller, more compact rhizomes. They have the largest flowers of all irises, and make wonderful spring accents for the edge of water gardens.  Japanese irises are the latest to bloom, about a month after the Siberian irises.

Iris germanica
Tall Bearded German Iris

No garden would be complete without Tall Bearded Irises. Though they have been grown for decades, new and improved hybrids continue to be developed every year and fabulous color combinations have been achieved. The Tall Beardeds bloom after the Dwarf Irises but before the Japanese and Siberian Irises. They are wonderful accent plants for late spring gardens.

Iris louisiana
Louisiana Iris

Louisiana Irises typically bloom after both Siberian and Tall Bearded Irises have finished blooming for the season. Flowers usually bloom on stalks at 2-3′ high, ranging from 3-7″ across in early spring.  Flowers come in blue, pink, yellow, purple, white and combinations. Mature clumps of this plant can grow up to 3′ wide.

Iris pallida
Sweet Iris

The brightly colored, striped foliage of Sweet Flag Irises effectively add interest and cheer anywhere they are planted. Their relatively short stature make them good for edging. These are the most reliable and disease-resistant of all Tall Bearded Irises.

Iris pseudacorus
Variegated Flag Iris

These plants thrive in standing water or very wet soils in full sun to part shade.  They also do surprisingly well in average garden soils.  Bright yellow flowers with a darker yellow zone bloom late spring to early summer on upright stalks atop sword-shaped green leaves.  Flowers give way to large seed pods. 

Iris pumila
Miniature Bearded Iris

This tiny treasure, introduced to the U.S. in the 1930s, was crossed with the tall bearded Irises to give way to a whole new type of dwarf. They basically look like an exact miniature form of the tall bearded iris.  They bloom very early in spring, before the tall bearded types.  Flowers are single usually with a darker spot on the falls in various colors.  Foliage is sword-like and clean. 

Iris sibirica
Siberian Iris

Siberian irises are haled for their elegant, delicate flowers and disease resistance. They perform admirably in the sunny to partially shady garden, but need plenty of water throughout the season to continue looking their best. In naturalized settings, they are particularly effective around water features. They can also be grown under Black Walnut trees since they are not effected by juglone. Siberian Irises bloom before Japanese Irises but after Tall Bearded Irises.

Information courtesy of Walters Gardens, Inc.

DIVIDING IRIS

Bearded irises usually bloom reliably for three to four years but produce fewer and fewer blossoms in succeeding years. This is because their rhizomes increase each season until they eventually become overcrowded and starved for nutrients. Dividing these clumps and replanting individual rhizomes in freshly prepared soil gives the plants a new lease on life allowing them to re-gain their blooming strength. The best time to divide irises in our area is in mid to late summer, so the new plants will have plenty of time to become established before freezing weather arrives.

1. DIG THE CLUMP
If the soil is dry, water the bed thoroughly a day or so before digging. When you have more than one variety scheduled for division, it is wise label each clump to avoid mix-ups. Use a pitch fork or spading fork to loosen the soil around and under the clump, taking care not to cut into the rhizomes growing near the edge. Lift the entire clump out of the ground and shake or wash away any soil clinging to the rhizomes and roots.

2. MAKE DIVISIONS
The clump will consist of older, spongy rhizomes with lighter-colored young ones growing from their sides. Cut the young rhizomes away from the older segments with a sharp knife. Discard the older pieces and any parts that are undersize or diseased. To reduce moisture loss, trim the leaves to about a third of their original height. Each division should consist of a vigorous, firm rhizome and a fan of healthy leaves.

3. CHECK FOR BORERS
In our area, bearded irises may be infested with borers, pinkish-colored larvae (or grubs) with brown heads. These creatures tunnel into and devour rhizome tissues, leaving a wound open to infection by bacterial soft rot. Extract and kill any borers you find, and cut away all damaged tissue. To help prevent infection, soak the rhizomes for about half an hour in a 10 percent solution of household bleach, followed by a dusting of powdered sulfur. Then lay the trimmed plants in a shady place for several hours to allow the cut ends to dry and heal.

4. RE-PLANT DIVISIONS
Always plant bearded irises in a sunny location with good drainage. First check for any borer pupae in the soil if you are replanting in the same location. Destroy them, or they will emerge in fall as moths and lay eggs on or near the new plantings. If possible, remove some of the old soil and add twice as much compost, or compost plus fresh soil. Also give the plants a light application of 5-10-10 fertilizer. Then, space the divisions 12 to 18 inches apart. Arrange them in a triangle with the fans of two of the divisions pointing outward, and the fan of the third pointed into the space between. To plant, dig a shallow hole for each division, forming a low mound in the center on which to set the rhizome. Drape the roots down each side of the mound, and firm the soil around them. It’s important to cover a freshly planted rhizome only lightly with soil. Those that are planted too deep are much more susceptible to borers and rot.

5. AFTER CARE
Water the young plants at once to settle the soil around the roots. If the weather is hot and sunny, temporarily shade them by placing a shingle on their south side. Irrigate every 10 days or so throughout the rest of the summer.

AWARD WINNERS

The Dykes Medal is the highest award given by the American Iris Society. It is awarded annually to only one Iris. Only AIS registered judges may vote for the winner. To be eligible for the award, the Iris must have won a classification medal in the previous 3 years.

Dykes Medal Winners

  • 1996 ‘Before The Storm’
  • 1997 ‘Thornbird’
  • 1998 ‘Conjuration’
  • 1999 ‘Hello Darkness’
  • 2000 ‘Stairway to Heaven’
  • 2001 ‘Yauquina Blue’
  • 2002 ‘Mesmerizer’
  • 2003 ‘Celebration Song’
  • 2004 ‘Crowned Heads’
  • 2005 ‘Splashacata’
  • 2006 ‘Jesse’s Song’
  • 2007 ‘Queen’s Circle’
  • 2008 ‘Starwoman’
  • 2009 ‘Golden Panther’
  • 2010 ‘Paul Black’
  • 2011 ‘Drama Queen’
  • 2012 ‘Florentine Silk’
  • 2013 ‘That’s All Folks’
  • 2014 ‘Dividing Line’
  • 2015 ‘Gypsy Lord’
  • 2016 ‘Swans in Flight’