Hostas are low-maintenance plants, popular in the home landscape because of the distinctive colors and textures of their foliage. Hostas are especially prized for their ability to grow and thrive in shady conditions. If your hostas are at least three years old, they'll benefit from being divided and repotted. As a result, you'll have a healthier hosta and at least one new hosta.
Replant hostas in early spring when the plant is just beginning to send up new shoots. Use a garden fork or a flat shovel to dig around the hosta, working 6 inches away from the plant. When you've made a circle around the hosta, slide the shovel underneath the plant and lift it out of the ground. Work carefully and slowly. With larger plants, this process will take some time.
Rinse the dirt off the hosta's roots with a hose and spray nozzle. Turn the hosta, and rinse the other side. Continue several times until the roots are mostly dirt-free, and you will be able to tell where to divide. Don't be afraid to spray with force. It won't damage the roots.
Look at the roots, and you will be able to see separate groupings of roots that will be obvious places for division. Use a sharp knife to cut between each clump of roots. Occasionally, you might be able to pull the clumps apart with your fingers.
Add at least shovel full of compost to the hole where the original hosta was removed, and work it into the soil. Replant the hosta in the hole and tamp the soil firmly around the plant.
Loosen the soil to a depth of at least 8 inches where you intend to plant the new hosta divisions, and work in some compost as directed above. Dig a hole slightly larger than the root system of the new hosta, and set the plant into the hole. Fill the hole with reserved soil and tamp it down lightly.
Surround both hostas with a 1-inch layer of mulch to conserve moisture and keep weeds down. Don't add excessive mulch because it can be a hiding place for slugs.
Water the hostas well and continue to keep them moist throughout the growing season. Hostas can withstand periods of drought, but too much dry weather will cause the leaves to turn yellow.