How to Divide a Daylily Clump

Does it need to be divided?
If plant is growing happily, blooming well, and does not look overcrowded in the garden, then leave it. If a clump is very crowded by plants next to it, has a donut shape with no foliage in the middle, and has fewer blooms than it did in previous years, then it's time to divide.

What time of year?
The best times to divide are when the plant is in active growth, either in April (when foliage is about 6" tall), or August-early September (soon after bloom finishes). Spring division may alter the timing of bloom, but will not prevent bloom for that year.

To Divide:
1) Cut back all foliage to half the existing height to off-set disturbance to roots.

2) Choose either the easy method (A) for older clumps, or the thorough gentler method (B) for more precious plants.

A) Easy-as-pie: Dig entire clump by inserting a sharp shovel 4-6" away from the base of foliage. Set clump on firm ground, slip a sharp spade or strong knife between sections of foliage, and slice through vertically, cutting the clump in half. Cut each half into 2 or 3 smaller wedge shaped pieces, like cutting a pie.

B) Wash-n-wiggle: Dig up entire clump with a strong digging fork (better than a shovel, which will cut off root tips). Repeatedly dunk and swish clump in a tub of water or spray with a hose to remove all soil. Look for natural separations between fans. Hold plant from opposite sides, grabbing down low where the roots meet the foliage, and wiggle back and forth until the clump loosens into separate sections. Rinse again and continue to gently pull off sections. Remember to hold down low, so you separate the roots from each other, rather than snapping off the foliage.

3) Before replanting, consider improving the soil by mixing in compost. Replant each piece with the top of the roots 1" below the surrounding soil. Add some organic fertilizer, backfill, and water well. Soak once a week for a month until established.