Key Points
Cut back warm-season ornamental grasses in fall for a cleaner winter look.Tie tall grasses into bundles before trimming to reduce cleanup.Trim invasive or fire-prone varieties in fall to control spread and lower fire risk.
As with lawn grasses, there are both warm-season and cool-season ornamental grasses. The warm-season types turn brown in the cold weather and are often cut back in fall, but in many cases, you don’t have to; an early spring trimming is also acceptable. This is a choice you will have to make, after weighing the pros and cons of trimming them before winter, based on your own needs and sense of aesthetics. The main con of a fall trim is that you may lose out on winter interest. Pros of a fall cutting can include:
Achieving a cleaner look in the winter landscape (especially relevant for the taller types of ornamental grass)Stopping an invasive plant from spreadingMinimizing fire risk if you live where wildfires are a known threat (the dry stems of ornamental grass would serve as kindling for a fire)
Here are some ornamental grasses that are often cut back in fall, why it may be best to cut this grass back in fall, and how far down it should be cut.
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ANGHI / Getty Images
Chinese silvergrass, or “maiden grass” (Miscanthus sinensis), can grow 4 to 12 feet tall. For this reason, those who like to clean up the landscape for winter tend to cut back this ornamental grass in fall.
Another reason to cut it back in fall and forsake the considerable winter interest it offers is that it is invasive (in the mid-Atlantic states and the Southeast).
Whenever you decide to trim it, cut it down to within a few inches of ground level (or, if you live in the North, leave a little more above-ground growth to furnish the roots with a bit of insulation).
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Striped ornamental zebra grass.
Credit: F.D.Richards/Flickr/Creative Commons
Zebra grass is a cultivar (‘Zebrinus’) of maiden grass. Reaching 7 feet tall, you may want to cut it back in fall if you live in an area prone to fires. Trim it down to within a few inches of soil level or just above it.
Minimize the Mess
Cutting down the dried stems of an ornamental grass can be a messy business. To minimize the mess, wrap something around the plant first to bundle it up. This could be twine, tape, etc. The idea is to transform it into a single unit (which is easily removed after making the cuts with your pruners) so that you do not have to pick up multiple stems later.
Pampas grass growing against a blue sky.
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Lizelle Botes / Getty Images
Pampas grass (Cortaderia selloana) can grow to 10 feet tall, making it a good candidate for a fall trim if you desire the “clean look” for your winter landscape. It is also an invasive plant in some regions, so trimming it in the fall in these areas can help to keep it in bounds. You can cut this vigorous plant down to ground level or just above it.
Purple fountain grass is treated as an annual in cold climates.
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The Spruce / David Beaulieu
There are different kinds of fountain grass, and not all are hardy in the North. For example, Pennisetum setaceum ‘Rubrum’ is only hardy in zones 9 and 10.
In such a case, the ornamental grass is treated as an annual in North, and you don’t have to worry about cutting it back. If you’re cutting back a variety that is hardy to your zone, trim it to within about 5 inches of the ground.
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While most types of switch grass (Panicum virgatum) don’t get overly tall, the ‘Blue Tower’ cultivar does reach 8 feet in height, so homeowners who prefer a neat and tidy winter landscape will cut it back in fall. Trim it to within about 5 inches of ground level or just above it.
Cordgrass
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gardendata / Getty Images
Cordgrass (Spartina spp.) is a great plant to grow in wet areas. But, under the right conditions, it can spread vigorously; a fall trimming may help to slow down the spread. Cut it down to within 4 to 6 inches of the ground.
Northern Sea Oats
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Northern sea oats (Chasmanthium latifolium) provides great winter interest, but it comes at a cost: If allowed to stand through the winter uncut, it drops seeds that will sprout up all over your yard. For this reason, it is a good idea to cut it back in fall.
To make up for the loss of winter interest, bring the stems indoors and place them in a vase, as the seedheads are highly ornamental (either solo or as part of a more complex dried arrangement). Prune it down to ground level or just above it.
Zen Rial / Getty Images.
Credit:
Zen Rial / Getty Images
Pink muhly grass (Muhlenbergia capillaris) is beautiful when in bloom but doesn’t offer much after that. For this reason, many choose to cut it back in the fall. Trim it down to within 3 to 6 inches of the soil surface.
Bunny Tail Grass
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Chiyacat / Getty Images
Bunny tail grass (Lagurus ovatus) presents opportunities and challenges similar to those for northern sea oats, so treat it as you would the latter.
If you let it stand all winter, it will reseed; to prevent this, cut it back in fall. Bring the stems indoors and place them in a vase to enjoy the puffy tops. Trim it down to ground level or just above it.
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