I do them in the spring, as soon as it's good enough to work outside, but before they have too much new growth. Water them well the day before. Dig a big clump, use a big knife or tree saw to cut it into pieces, making sure each piece has some new green growth starting. Plant the pieces right away, water well and they will be fine.
You can also do them in the fall, but it's a bit early for that. I would wait until late September. Use the same process described above.
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I usually dig and split mine in the Spring when they are less than 6" high.
They are easy to find, dig and transplant when this small.
I have also moved a couple when they are a foot tall. Usually causes a bit of leaf damage but they survive just fine.
I try to do all my transplanting when a rain is expected or just after a good rain when everything is well soaked.
If you need to move or split one now, go ahead but you will do alot of leaf damage during the move unless it is a small hostas.
Always transplant the new ones to a similar sun/shade area as the place it was originally planted and water well after planting.
I do them in the spring, as soon as it's good enough to work outside, but before they have too much new growth. Water them well the day before. Dig a big clump, use a big knife or tree saw to cut it into pieces, making sure each piece has some new green growth starting. Plant the pieces right away, water well and they will be fine.
You can also do them in the fall, but it's a bit early for that. I would wait until late September. Use the same process described above.
split them in fall right before the estimated first frost
in the fall when they are dormant