Hostas, sometimes known as plantain lilies, are popular herbaceous perennials valued for their lush foliage and ability to thrive in shaded environments. These plants grow by expanding their root crown and producing new shoots, or “eyes,” which leads to an ever-widening clump. Gardeners often divide hostas when the plants become overcrowded, resulting in a dense center that may begin to decline in vigor. Division also serves as an effective method of propagation, allowing a single mature plant to be separated into multiple new specimens for relocation or sharing. This process ensures the continued health of the hosta and rejuvenates the planting area.
Choosing the Right Time and Tools
The best times to divide hostas are during the early spring or early fall, as these periods minimize plant stress. Spring division should occur when the “eyes,” or pointed buds, are just emerging but before the leaves have fully unfurled, a window typically lasting about four weeks. Dividing the hosta while dormant reduces the demand for water, which is important since the foliage is often damaged during the process.
Fall division is beneficial because the plant’s growth has slowed, but the timing must allow new divisions to establish roots before the ground freezes. This window usually spans September in northern climates and extends into October further south, taking advantage of cooler, moist weather. Necessary equipment includes a sharp spade or garden fork for digging and a utility knife or sharp trowel for precise separation. A tarp placed near the work area helps manage the displaced soil and the heavy root ball.
The Process of Lifting and Dividing
Proper preparation involves watering the hosta thoroughly a day or two prior, which hydrates the plant and makes the soil easier to work. To lift the entire clump, sink the spade vertically into the ground, creating a circle 6 to 8 inches away from the crown to minimize root damage. The depth of the cut may vary, as some hosta root systems can extend up to 18 inches deep.
Once the circle is cut, angle the spade toward the center of the plant and use the tool as a lever to gently pry the entire root ball from the soil. Place the lifted clump onto a tarp and remove excess soil by shaking or rinsing to expose the crown and roots. The goal of division is to ensure each new section has a healthy portion of roots and at least one to three “eyes” or buds.
Use a sharp, clean cutting tool to slice the root ball into the desired number of pieces, aiming for a clean cut to prevent disease entry. For very large clumps, a sharp spade can be used to chop the root ball into halves or quarters. Smaller divisions require a knife to separate individual eyes while preserving intact roots. The fewer roots that are cut, the faster the new division will recover.
Replanting and Post-Move Care
Immediately after division, the new planting location should be prepared to minimize the time the roots are exposed to air. Dig a hole that is approximately twice as wide as the root mass but only as deep as the root ball itself. This wide, shallow hole allows the roots to spread outward into loosened soil, promoting rapid establishment.
The new division should be placed so that the crown—the junction where the shoots meet the roots—sits precisely at the surrounding soil level. Burying the crown too deeply can lead to crown rot, while planting too shallowly may cause the roots to dry out. Backfill with soil, ideally amending it with compost to improve drainage and provide nutrients.
The most important step following replanting is deep watering, which settles the soil and removes air pockets. Consistent moisture is required during the first few weeks, as the hosta’s reduced root system struggles to supply water to the existing foliage. Applying a two- to three-inch layer of organic mulch around the plant, keeping it clear of the crown, helps maintain soil moisture and protects the plant from sun shock.