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YARD AND GARDEN

August time for transplanting iris

David Robson

August is one of those middle-of-the-road months, like March and October, for gardeners. There isn't a lot that has to be done, but I have a few suggestions. Since becoming a homeowner, I generally allow the yard and garden to take care of themselves during the month, with an occasional foray out to clip off dead flowers and search for bugs, slugs and other garden thugs that can quickly get the upper hand. Early, early morning hours are the best time, but the body quickly overrides the mind, so sunset becomes the alternative.

It seems hard to believe, but August is a great time for transplanting a few of the garden perennials. None more so than iris. Daylilies and peonies aren't far behind, though we could relegate them to the first of September.

Iris are seldom remembered in August's furnace. They've already bloomed and more than likely are hidden by other flowers. Still, the flat fan architectural form is a great contrast to the bushy round forms of most plants. Add the fact that leaves are a cool ice blue, and you have some form of garden interest even without flowers.

By August, the iris have formed the growth for next year's blooms. Dividing them now gives them an opportunity to establish new roots for the winter and not miss the bloom cycle next spring. Iris tend to bloom once on each fan, and that's it. Mark a bloom next May if you remember and see if it blooms in 2002. Iris have adapted almost as well as cockroaches. They'll produce one or two new fans for each old fan. Even old non-blooming fans will produce new growth year after year. But the catch is, there has to be room for the new growth.

The iris rhizomes don't always produce new growth away from the plant. Sometimes they start" growing back on themselves. And if there is no room for growth, no new fans are formed. That's why it's important to divide the plants every three to five years, in the hottest part of the summer, when most sane people are still indoors enjoying a cool one.

If you divide and move the iris in spring, they may not bloom the next year for you as the plant is spending its energy producing new roots instead of new growth when it's cool. If you divide and move plants in the fall, they may not have enough time to root before winter. This follows for just about all iris including the common bearded, Siberian, Japanese and Louisiana types. About the only ones you don't divide now are the bulbous types.

Dig up the clump. This may be easier said than done for Siberian types that form a clump as dense as some ornamental grasses. You may think a backhoe is needed. Trust me, just wet the clump thoroughly and wait a day. Remove the centers of the clumps and deposit them in the compost pile. They tend to be the old plants. Keep the young, smaller ones at the edges.

For the common bearded iris, take a sharp knife and cut the rhizomes (horizontal woody stems) so that there is at least one fan and some good roots per piece. Feel the rhizomes by lightly squeezing them. If they are soft, throw them away. More than likely, you have soft rot or iris borers.

Till the soil and add some organic matter. Plant the iris piece an inch below the ground and lightly firm the soil. Water. Some gardeners cut the fans back by half to reduce the water stress. This doesn't hurt, but make sure the scissors are sharp and you don't tear the leaves.

For clump-type iris, lift the clump, take a sharp knife or spade and divide the clump into several chunks. You might not be able to remove the old ones, but just dividing the clump should help it. Do not mulch iris. They'll rot. Keep the clump moist, but not soggy for a week or so.

16 ILLINOIS COUNTRY LIVING • AUGUST 2000