When Should I Cut Down Ornamental Grasses?

When Should I Cut Down Ornamental Grasses?

Here on the Cape people sometimes call ornamental grasses “beach grass” although they are not usually varieties that grow on the beach. But to those who live near the beach the blades of a Miscanthus (aka Japanese silver grass) or a Pennisetum (fountain grass) shine and move in the breezes just like the foliage of the true American beach grass (Ammophila breviligulata) that grows on sand dunes. But no matter which type of grass is in the landscape, or what name it’s called, people wonder if they should cut these grasses down in the fall or leave them all winter. The bottom line is this: there is no one right answer. If you’re in the mood to clear things out in the fall, by all means cut the grasses down in November, leaving about 6″ of stem.

Here are some photos that show the advantage of leaving grasses in place. 

One reason people leave grasses is that they are most beautiful in the fall and early winter. In the fall their seed heads sparkle in the sun, and they are lovely when dusted by the first snowfall.

One reason people leave grasses is that they are most beautiful in the fall and early winter. In the fall their seed heads sparkle in the sun, and they are lovely when dusted by the first snowfall.

You can even gather the taller grasses up in early December and decorate the clump for the holdiays.

You can even gather the taller grasses up in early December and decorate the clump for the holdiays.

Whether using a single bow or a spiral of ribbon from top to bottom, these Miscanthus look splendid tied for the holidays.

Whether using a single bow or a spiral of ribbon from top to bottom, these Miscanthus look splendid tied for the holidays.

Sometime in late-January or February, however, the clumps of grasses start looking weather-worn. The plumes have mostly blown off, and often the stems have become bent and broken by snow and wind. Time to clear them out!

Sometime in late-January or February, however, the clumps of grasses start looking weather-worn. The plumes have mostly blown off, and often the stems have become bent and broken by snow and wind. Time to clear them out!

The most important thing to know about cutting old grasses down is to do it before the new blades come up on April. So anytime from late-January through March is best. Don't leave too much of the old grass as it will just make the new growth look messy. Cut the stems down to about 6" from the ground. Hedge trimmers are the fastest way to cut if you don't have a high-powered, gasoline powered shearing tool.

The most important thing to know about cutting old grasses down is to do it before the new blades come up on April. So anytime from late-January through March is best. Don’t leave too much of the old grass as it will just make the new growth look messy. Cut the stems down to about 6″ from the ground. Hedge trimmers are the fastest way to cut if you don’t have a high-powered, gasoline powered shearing tool.

 

7 Comments

  1. Amanda Murphy on November 5, 2015 at 8:00 am

    LOVE your newsletter, love your photos…keep ’em comin’!

  2. Roseann on November 5, 2015 at 9:04 am

    One of my ornamental grasses has become too big for the garden it is currently in. When is the best time to transplant it to another garden? I am guessing in the Spring? If that is the case, do I do it before or after new growth is visible. Thank you.

    • CLFornari on November 5, 2015 at 10:57 am

      Roseann,
      Moving them in the spring is the brest. You can either move the entire clump, or dig it up and cut off a section of the outermost growth (the newest growth) and plant that elsewhere. As grass clumps age they tend to die out in the center, so carving off a piece of the newest growth makes sense if you’re going to the trouble of digging them up.

  3. Mary on November 5, 2015 at 10:09 am

    I cut them if they maybe invasive. If you know there not enjoy.

  4. Barbara on November 5, 2015 at 1:28 pm

    I purchased and planted an ornamental grass in 2014 in the late summer. I cut it down to within 6 inches in its first winter. The next spring only the outer rim of the ball sprouted (the center did not sprout new growth).
    Will the center eventually come back or will the ball never recover fully? How can it be helped along?

    • CLFornari on November 10, 2015 at 4:08 pm

      Barbara – it’s often best the first year to leave grasses in place over the winter and only cut them down in the following spring. Usually when grasses die out in the center they don’t come back, but if the growth around the edge did well this year that should get larger next year. You can cut the largest section off in a chunk and dig the rest out to throw it away, replacing the chunk in the ground. This will help the clump to look fuller. Do that in the spring.

  5. Ellen Temkin on November 21, 2015 at 12:15 pm

    I love receiving your interesting newsletters. thank you

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