Using Bearded Iris in Your Landscape

While there are more than 150 species of iris, only the bearded iris will be discussed here as this is the most commonly grown and recognized species.

Those who visited the iris garden of Dorothy Britton on the garden tour this spring were delighted by the spectacular display of over 750 iris varieties. Ms. Britton graciously invited the Master Gardners to tour her home garden, and guests had the opportunity to select their choices and place orders for delivery at the proper planting time.

The bearded iris is a good choice for Cochise County yards and gardens. It is one of the easiest perennials to grow, it adapts well to most soil conditions, it is not a heavy feeder, and does not require a large amount of water. Although the iris grows well in full sun, it thrives in light shade in hot climates. Being native to cold winter areas of Europe, the iris rhizome is not harmed by Cochise County's winter temperatures.

The many iris varieties are useful for foundation plantings, are good in borders or beds around yards and patios, and along pathways. With the huge selection of colors, and combinations iris are beautiful when viewed from up close - many have the added attraction of fragrance. When grown in large clumps of a single variety, iris put on a magnificent display even when seen from a distance.

Now that summer is here, the time for planting iris is approaching - usually from July through September. It is during these months that Iris growers ship plants, and they become available locally in garden shops. Friends and neighbors who have iris plantings are also good sources of rhizomes (the thick, tuberous-like stem that lies just under the ground and from which the leaves and roots grow) since many iris are quite prolific and the older, dense clumps should be dug, divided, and replanted soon after they finish blooming.

Prepare the soil prior to planting by digging at least one foot deep. The inclusion of some organic matter at this time is helpful to improve the drainage as Iris will rot if left landing in puddles of water. A small amount of balanced fertilizer (i.e. 6-6-6 or 10-10-10) dug into the planting hole at this time will be helpful. Do NOT use heavy additions of nitrogen which cause lush growth but few flowers.

Plant iris rhizomes horizontally - the tops of the rhizomes should be just under the level of the soil surface. If planting them in a row, space the rhizomes 8-12 inches apart; the rhizomes should all face the same direction resulting in a uniformly expanding row of plants. If clumps are desired, plant the rhizomes in a circle (3 or 4 per circle) with the root ends toward the center and the growth ends facing outward. This allows growth for several years before division of the clumps is necessary.

Plants require water during active growth and blooming periods - water deeply about once a week. Unless the weather is very hot, watering is not necessary at other times of the year for established plants. A light feeding of a balanced plant food is desirable each year in early spring.

Iris bloom lightly the first year after planting, then more heavily each year- until by the fourth year the amount of bloom has decreased. Dig the iris clumps every 3 to 4 years and wash off the dirt with a heavy spray from the hose. Separate the plump, healthy rhizomes with a sharp knife discarding any that are old, shriveled or mushy (rotted). Cut off the leaves to about 6 inches to reduce wilting. Leave the iris outside for 2 or 3 days to allow the air to "heal" the cuts, and then replant. With a minimal amount of care, bearded iris will return a maximum amount of springtime pleasure.

*Carole Cox is a student in the current Master Gardener class - a "soon-to-be" Master Gardener!

Carole Cox
May, 1993