Do I Dig Up the Whole Hosta When Separating It?

Hostas are undemanding plants with large heart-shaped leaves that grow in shade. They bear small lavender or white trumpet-shaped blooms in summer on tall stalks that rise above the foliage. After three to four years, they will have multiplied to form a tight clump with many crowns and can be divided and replanted.

Timing

Divide hostas in spring, just as they are pushing their tips through the soil. Dig up the whole clump, using a garden fork. After shaking or washing off the soil, you will be able to see the separate crowns more clearly. Carefully tease them apart or cut the clump into four or five pieces, each with tips and roots. Hostas also can be divided in late August, but no later than 30 days before first frost. The sieboldianas and tokudamas should be divided then, not in spring.

Replanting

Amend the planting area with compost, mixing it half-and-half with the soil. Form a cone of soil in the bottom of the hole and set the division on top of it. Fill with soil about a third of the way up, then water to settle it. Repeat until the soil of the hole is level with the surrounding soil. Water, then mulch. The tips of the hosta should be showing at the same level they were when you dug it up.

Aftercare

Newly divided plants need regular water during their first year to establish a strong root system. Mulch plants in fall for the first winter. Thereafter, hostas are hardy, drought-tolerant perennials that bring valuable texture and color to the shade.

Pests

Slugs and snails are the most common hosta pests. Thwart them by using iron phosphate slug bait, which is safe for pets and wildlife, or by searching for them in moist, cool weather and tossing them into a solution of 1 part ammonia to 1 part water. Deer also love to dine on hostas, so spray the leaves with deer repellent and reapply it after rainfall.

References

• Ohio State University Extension: Growing Hostas; Gretchen Heinke; Jane Martin
• Green Hill Hostas: Bob Solberg's Hosta Gardening Tips