Hostas are popular shade-loving perennials grown for their lush foliage. Trimming is necessary, but the type and timing depend on the season. Throughout the growing season, targeted maintenance improves the plant’s appearance and health. The most extensive trimming occurs in the fall to prepare the plant for winter dormancy and ensure robust growth the following spring.
Trimming the Flower Scapes
Hostas produce tall, leafless stalks called scapes, which hold tubular, often fragrant, white or lavender blooms between early summer and mid-fall. Removing these scapes, known as deadheading, is largely an aesthetic choice, but it also redirects the plant’s energy. If you prefer to focus on the foliage, use clean, sharp shears to snip the scapes at the base before the buds open.
Allowing the flowers to bloom attracts pollinators. Once the blooms fade, remove the scapes to prevent the plant from expending energy on setting seed. This conservation promotes the development of new leaves and roots. Cut the entire flower stalk close to the foliage crown once three-fourths of the flowers have finished blooming or when the scape looks ragged.
Removing Damaged or Diseased Leaves
Throughout the spring and summer, hostas are susceptible to damage from pests (slugs and snails) or environmental factors (hail and sun scorch). Removing these compromised leaves maintains the plant’s appearance and prevents further problems. Use clean scissors or pruners to cut the leaf petiole (the stem connecting the leaf blade to the crown) as close to the crown as possible.
Immediate removal is necessary for leaves showing signs of disease, such as Hosta Virus X (HVX). HVX manifests as mottled or distorted foliage, often with dark, vein-centered discolorations called “inkbleed.” Since HVX is highly contagious and spreads through contaminated sap on tools, affected plant parts must be removed immediately. Pruning tools must be thoroughly disinfected before touching another hosta. Dispose of diseased material and any suspect plants in the trash, not the compost, to avoid spreading the virus.
Essential Fall Cutback
The most extensive trimming happens in the late fall as the plant prepares for winter. This annual cutback is performed after the first hard frost, which signals the plant to enter dormancy. After a hard freeze, the leaves turn yellow or brown and become limp, indicating the plant has translocated energy reserves back into the roots and crown.
Cutting back the spent foliage prevents overwintering pests and diseases. Decaying leaves provide a favorable habitat for slug eggs and can harbor fungal spores that infect new growth the following spring. Use sharp, clean pruners to cut all the foliage down to about two inches above the soil line, leaving a small stubble to mark the plant’s location. Promptly remove all cut foliage from the garden bed to reduce the risk of infestations and disease.