AMES, Iowa – Putting the garden to bed for the winter is a matter of cleaning up and covering up. Horticulturists with Iowa State University Extension and Outreach have recommendations on cutting foliage as part of fall clean up. To have other fall garden questions answered, contact the Iowa Hortline at email@example.com or call 515-294-3108.
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 2 to 4 inches of the ground with hand shears, lopping shears or hedge trimmers.
Cut back peony foliage after it has been destroyed by a hard freeze. In Iowa, late October or early November is generally a good time to cut back peonies. Cut off the stems near ground level. If the peonies experienced foliar disease problems, remove the plant debris from the area and destroy it.
Plants cut back in August or early September may have fewer blooms that those cut back in fall.
The asparagus foliage can be cut back to the ground after it has been destroyed by cold temperatures in fall. However, it is generally recommended that the dead foliage be allowed to stand over winter. The dead debris will catch and hold snow. Snow cover helps protect the asparagus crowns from freeze damage. Asparagus foliage allowed to remain in the garden over winter should be removed in late March or early April before spears begin to emerge.
Garden mums have shallow, fibrous roots. Repeated freezing and thawing of the soil during the winter months can heave plants out of the ground and cause severe damage or even death. Research has found that garden mums are more likely to survive the winter when plants are left standing over winter. For additional winter protection, cover garden mums with several inches of straw or pine needles in late November or early December. Remove the mulch in early spring (April). Also remove the dead mum debris at this time.