Gardenality.com · Gardenality Genius · Zone 8A · 10° to 15° F · Comment About Planting
Bearded iris are easy to grow in average to rich well-drained soils. If you are planting bare root rhizomes don't bury them too deep. When planting a container-grown bearded iris dig a hole three times the width of the root ball. If your soil is good add a few handfuls of compost to the mix. If your soil is heavy clay mix composted organic matter at a 50/50 ration with the soil removed from the planting hole. Avoid using composted manure products. Mushroom compost or your own homemade compost will do. Set root ball in hole at the same depth it was growing in the pot, with the top edge of the root ball at ground level. Backfill around root ball tamping as you go to remove air pockets. Water thoroughly after planting and if you apply any mulch make sure it is a very light coat. Too heavy o0f mulch can cause the rhizomes to rot.

DIVIDING BEARDED IRIS

You can divide bearded iris anytime after flowering through August or in early spring when new growth begins to emerge. Healthy iris plants should be divided every third or fourth year. The rhizomes branch like a fork and grow outward from the back of the fan of leaves. Dig the plants with a spading fork and gently pull apart the divisions. Once you have the bearded iris rhizomes lifted, shake off any loose soil. Rinse off any remaining soil with a garden hose. Once the rhizomes are cleaned, you can separate the individual rhizomes from one another. Don't break them apart, just loosen the already separate sections. Cut back the foliage to about six inches. Examine the rhizomes carefully for signs of problems, such as rot or borers or soft rot, keeping only healthy rhizomes. Generally the vigorous portions are the younger parts of the clump. You will see natural places to make a split, such as where the rhizome has forked. Study the rhizome and make sure each section you have chosen will wind up being at least 3 inches long and will have healthy roots growing from it. Then you can cut the rhizomes apart. To transplant, start by digging a shallow hole that will be wide enough to spread out the rhizome's roots. Make the hole about 2-3 inches deep, then create a mound in the center of the hole to just about soil level. Place the rhizomes on top of a ridge of soil and spread out the roots. Cover with no more than 2 inches of soil, making sure the rhizome is partially exposed. When the soil has been firmed and the plant watered, the rhizome should be half-exposed out of the soil.

Gardenality.com · Gardenality Genius · Zone 8A · 10° to 15° F · Comment About Pruning
Remove the flowers of bearded iris as soon as they finish blooming. Pinch the spent flowers off behind the flower head and discard them leaving the flower stems on the plant. When all the buds have opened and finished blooming you can remove the entire flower stalks. Using a sharp pair of pruners cut the flower stalk off where it emerges at the base of the plant.

Damaged or diseased leaves can be removed throughout the season by cutting them off the level of the soil. Remove only the damaged or diseased leaves. In fall, when the foliage has yellowed and died back naturally, you can remove it.

Gardenality.com · Gardenality Genius · Zone 8A · 10° to 15° F · Comment About Feeding
Bearded iris are not heavy feeders and do not like fertilizers high in nitrogen (the first number in fertilizer.) I feed irises with a slow release organic plant food in spring when new growth begins to emerge.

Gardenality.com · Gardenality Genius · Zone 8A · 10° to 15° F · Comment About Problems
Iris borers are one of the few problems with bearded irises. This insect begins as eggs laid late in fall on iris foliage and rhizomes. In spring, the next stage burrows into the foliage and rhizomes and develops through the summer into a gray, wormlike creature around an inch long. In early summer, you might be able to see tracings where they are traveling around inside the leaves. By mid summer the borers are in the rhizomes. In late summer the borers leave the irises and pupate in the soil until fall when they hatch into a small, indistinct moth that starts the cycle over again by laying new eggs on the irises. The foliage on irises that is affected by iris borers will have yellow and brown edges and the rhizomes will have holes chewed through them. Whenever you find evidence of borers, it is important that you dig the rhizomes and examine them, replanting only those that are healthy. University studies have shown positive results in controlling Iris bore by beneficial nematodes.