To maintain bearded irises in good blooming condition – trim. It’s necessary to dig and divide the clumps every three or four years.
Mid to late summer is an excellent time to dig the clumps, so the new divisions will have plenty of time to make new roots before cold weather stops all growth activity.
The bearded iris will grow in poor soil, but for prize-winning blooms, it is wise to use a good garden fertilizer such as a 5-10-5 formula and to work plenty of organic material into the planting bed. A sunny, well-drained location protected from strong winds will produce gorgeous blooms.
Digging Bearded Iris
To dig, encircle the entire clump with a spading fork and pry the clump out of the ground. Wash away all soil from the matted rhizomes and cut away the tops so that only six-to eight-inch fans remain.
Cutting and Dividing Iris Clumps
With a sharp knife cut into each rhizome, saving the stout white roots and removing the old spent tip of the mother rhizome. The solid young rhizomes on the outside edge of the clump are the best ones to keep.
Remove all rot from the rhizomes and dust the divisions with a good fungicide powder.
Resetting Bearded Iris Plants
In a well-prepared planting bed, set the rhizomes on ridges of soil with deep pockets on either side to hold the fleshy roots.
If planting in clumps, set the rhizomes with the tips inward toward the center of the clumps. Since growth will be away from the tips of the rhizomes, this will prevent unnecessary early crowding.
Water the entire planting down thoroughly. In case of drought, soak the soil thoroughly – Read: How to Use Soaker Hose – every ten days to maintain maximum growth as long as possible.