If you’re needing some extra plants, dividing the overgrown ones you have is a good way to increase your stock. While not all plants fare well when divided in the summer (see reference), daylilies, hosta’s, liriope, and coral bells can be successfully divided and replanted in their new spots.
There is one caution to dividing in summer! These plants will lose all their leaves after being transplanted. But not to worry, in two to three weeks, you’ll see new green emerging and your new plants will be well settled by the time cold weather arrives and they’ll have a head start for spring. Do this now if you have first frost in late September.
Selecting Overgrown Plants
Select any oversized hostas or daylilies or plants named above and dig down all around the plant so you have all of the root ball possible. Pull the root ball out and lay it on its side. With a sharp spade or knife, begin cutting out the size plant you want. You can go as small as one square inch or divide the plant into larger pieces. Just be sure to have a good piece of root in each cut.
How to Plant Cuttings
An average 12 to 18 inch full grown hosta or daylily can give you as many as 10 to 12 new plants. Dig a hole for your new plant and add a good scoop of compost. Then bury the roots and about 1 inch of the foliage. Again, the foliage will die off, but if you water the transplants well every few days, you will see new growth in 2 to 3 weeks.