Yard And Garden: When To Cut Back Plants

By Richard Jauron

When is the right time to cut back plants in the home garden? It depends on the plant. Iowa State University Extension and Outreach horticulturists offer tips on cutting back perennials, ornamental grasses, asparagus and rhubarb. To have additional questions answered, contact the ISU Hortline at 515-294-3108 or hortline@iastate.edu.

When should I cut back perennials?

Most perennials, such as peonies, daylilies and hostas, can be cut back in November after a hard freeze has destroyed the above ground growth. If fall cleanup isn’t possible, remove the dead debris in early spring.

When should I cut back ornamental grasses?

Many ornamental grasses provide color, sound and movement to the winter landscape. Because of these winter features, cut back ornamental grasses in April in Iowa. Cut back the grasses to within 3 to 4 inches of the ground with hand shears, lopping shears or hedge trimmers.

When should I cut back asparagus?

Asparagus foliage can be cut back to the ground after it has been destroyed by cold temperatures in fall. However, it’s best to allow the dead foliage to stand over winter. The dead debris will catch and hold snow. Snow cover helps protect the asparagus crowns from cold winter temperatures. Asparagus foliage allowed to remain in the garden over winter should be removed in late March or early April before spears begin to emerge.

When can I cut back rhubarb plants?

Don’t cut back the rhubarb until the foliage and stalks have been destroyed by a hard freeze. To produce a good crop next spring, rhubarb plants must manufacture and store adequate levels of food in their roots. The foliage continues to manufacture food as long as it’s healthy. Once destroyed, the foliage and stalks can be removed.  

Source:iastate.edu