Iris beds need "thinning" periodically (every two or three years). September is the ideal time to plant or to divide and replant iris - the common man's orchid. Here's how it's done. Before digging rhizomes (roots), cut leaves back to about one-third their full height.

When can you thin out irises?

Mid- to late-summer is a good time to divide bearded irises. You want to make sure that the roots have ample time to grow before winter. You can usually tell that your irises are ready to be divided when a clump looks overgrown, with rhizomes starting to grow into each other and popping up from the soil.

When can you dig up iris bulbs and replant them?

The best time to dig up iris bulbs or rhizomes in the garden is between the last days of summer and early fall. Lift the clump of iris plants from the ground with a spade or fork. Try to lift the entire bulb to ensure the plant survives the move.