Ornamental grasses are more popular than ever, and for good reason. They can add texture to the landscape, and they are tough plants that are easy to grow in a variety of conditions. 
Ornamental grasses can also add beauty to the winter landscape.
But should ornamental grasses be cut back to the ground in winter?
Most ornamental grasses develop tall seed heads late in the summer that naturally persist through the winter. When temperatures start to drop the plant will die back, leaving the dried foliage, stalks, and seed heads. The general rule that you should cut back the grasses before the next growing season, so that the new year’s growth will be more vigorous and healthy.
I have found a couple of exceptions to this here in the Denver area, particularly with Mexican Feather Grass (Nassella tenuissima), which did not regenerate as well or look as good the year after I cut it back. I have since started leaving it uncut, which results is the new growth coming up right through the beautiful finely textured golden old growth. But with most varieties, they should be cut back before new growth starts in the spring.
So the question, then, is whether you should cut them back in the fall, or wait until the spring. Many people enjoy the colors and movement that these elements provide in winter. Others prefer a more “neat” or formal look.
I thought it would be interesting to explore the advantages each approach:
Advantages of leaving the grasses for the winter and waiting until the spring to cut them back
- When shrubs lose their leaves, and perennials wither to the ground, grasses can provide form in the landscape
- Texture: Interesting textures can stand out, collecting frost or snow, and reflecting sunlight
- Movement: Winter winds and soft breezes can move and sway the stems and seed heads of ornamental grasses
- The grasses can add color to the drab winter landscape, including shades of reds, yellows, browns, and blues
- Upright grasses can be used to help screen views when deciduous plants have lost their leaves
- The grasses can provide habitat and shelter for birds and other small animals
Advantages of cutting back ornamental grasses right away in the fall or early winter
- This can be interesting and different look, I have seen some nice formal plantings that looked stunning with the grasses cut back
- Some grasses hold their form better than others, while some varieties may flop over under heavy snow
- Cutting them back may give the impression (rightly or wrongly) that a commercial landscape is being better maintained
- In some cases the grasses may block sight lines, such as to important signage in a shopping center
- In high foot traffic areas, it may be beneficial to cut back ornamental grasses to avoid them being trampled
So what do you think, is one method better than the other? My personal taste is to leave the grasses up all winter, but there are situations where you may want to cut them back. And you can always decide to cut them back later, if you feel the need to tidy them up.
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The landscaper cut back my grasses in early fall, now they are hardly growing at all. Is there any help for them?
Hi Charlene, do you have any photos? What time of year they are cut back (fall or spring) shouldn’t really impact their health, it’s really more of an aesthetic choice.
MY GRASSES DIE IN THE CENTER AND EVERY YEAR THE CIRCLE GETS BIGGER AND BIGGER(GROWTH IS THE OUTER RIM)THAT NORMAL?DO YOU TRY AND DIG OUT THE CENTER?THEY SEEM TO HAVE A VERY STRONG(HARD TO DIG UP)ROOT SYSTEM.PLUS,IF YOU WATER LESS WILL THEY GROW SMALLER VS A LOT OF WATERING AND GETTING QUITE LARGE THANKS FOR YOUR HELP
Bob,
Yes it is normal for ornamental grasses to die out in the center. To overcome this situation, you can divide the grasses, remove the dead material, and replant the divided up and still living portions of the grasses. It is best to divide the grasses in the Spring time when temperatures are cooler than the summer, and before the grasses have put out much new growth and before they have started to put out their “flowers”.
I recommend doing an internet search on “how to divide ornamental grasses”. I also recommend books such as “THE COLOR ENCYCLOPEDIA OF ORNAMENTAL GRASSES” by Rick Darke, an expert on growing ornamental grasses.
Can grasses be cut back while they are still green or would I need to wait until they turn brown?
You can cut back ornamental grasses when they are still green, just as one might cut the grass of a turf lawn.
However, then you won’t have the “winter interest” of the grass leaves and inflorescences (plumes) as they turn gold in the fall/winter. Another advantage of keeping the green leaves is that they help feed the roots as the plant is preparing itself for winter.