Proper Maintenance Practices for Ornamental Grasses

Ornamental grasses add color, texture, and movement to the garden. They are an integral part of every gardening style. However,  grasses pruned at the wrong time will surely suffer, begin to decline, and ultimately give grasses a bad name. With the right knowledge, they are perhaps one of the easiest plant groups to care for, requiring maintenance only once a year.

Muhlenbergia ‘Regal Mist’
Cool Season Grasses vs. Warm Season

Ornamental grasses grow according to temperature and are split up into two groups–cool season and warm season.

Cool season grasses start to grow in early spring. Some examples include Fescue, Calamagrostis ‘Karl Foerster’, and Nassela (Mexican Feather Grass.)

Warm season grasses look better during the summer through fall: Bouteloua gracilis ‘Blonde Ambition,’ Pennisetum sp., Muhlenbergia, Panicum, Sorgastrum.

Bouteloua ‘Blonde Ambition’
When to Prune

Pruning grasses at the right time ensures their future success.

Cool season grasses should be pruned in October-November in preparation for seasonal rains and a new growth period. Warm season grasses should be pruned in late winter/ early spring, February-March, in preparation for spring growth.

While there are general time periods for pruning both warm and cool season grasses, ultimately, the grasses themselves will provide the cues for the proper time to cut them back. Only prune at beginning of the growing season when approx. 2-3” of new growth has emerged from the base.

How to Prune

Only cut flat across the top: NO orbs, domes, rockets, or torpedoes! These odd shapes cause the plant’s slow death, leaving dried “nubs” in the landscape that no one wants to see.

When too much old growth is left from the previous season or pruned at the wrong time, sunlight and air cannot get to the base of the plant where new growth starts, thus leaving the plant unable to regenerate itself properly. See attached handout.

Grasses are an amazing addition to the landscape providing wonderful texture, color, accent, movement, luminescence, and beauty with years of almost carefree maintenance. Let’s all help keep grasses beautiful throughout the year by embracing proper maintenance practices.