Ornamental Grasses

May 2012

What should I do for my clumps of pampas grass? Cut back in early March, close to the ground, but with a little higher mound in the centers....the centers have not started growing...we cleaned out the old debris when cutting back. They are 4-5 years old. We must be doing something wrong...should they have been cut flat to the ground? Any help you can give me will be appreciated.

If you missed a few years in the past cutting it back, the old growth can die back to the crown and cause the center of the plant to rot. Unfortunately, you need to dig up the plant at that point and throw away the dead crown or you have a green donut in the landscape, and it won’t set any plumes—the main reason people are planting it. I think it is easier to simply plant a new one or a different ornamental grass. Rarely can you cut pampas grass level with the ground, usually 12-18 inches is about the lowest you can get it.

March 2012

My pampas grass is still green. Usually, I cut it down to a mound about 4 or 5 inches high. Should I do the same this year even though it is not brown and dead looking.

You aren’t alone. Our mild winter has most pampas grass staying at least half green. However, to make way for the new growth, I would still cut back the old. Pull back the old growth to see how tall the new growth is, and cut above that. You don’t have 100% green, but it is much greener than normal.

December 2009

I have quite a few ornamental grasses in my garden, including the perennial pampas grass, purple muhly grass and miscanthus, but I also have some of the new annual grasses. Do I do anything different when cutting those back? Could I cut the grasses back this fall or do I need to wait until February?

Ornamental grasses of all types are at their peak of glory in the fall and winter. Even though the tops of both the annuals and perennials are dead after a killing frost, we like to leave the foliage and plumage out there for winter color, texture and interest. Cutting them back before new growth begins in late February gives you the most enjoyment out of them. It won’t hurt the plant to be cut back now, but it won’t be very attractive in your garden. As to the annuals, pulling up the whole plant, roots and all in the spring before you replant is all that is needed.

February 2010

How and when do you prune Pampas grass--or do you?

Yes you do. Pampas grass, along with all ornamental grasses should be cut back before new growth begins. Pampas grass can be tough to cut. Some folks use a chain saw, (reversing the blade direction seems to make it easier), while others use hedge trimmers. You won’t be able to cut it flush with the ground, but taking off the majority of the old foliage will give you a healthier and cleaner plant. Do it every year in late February to early March.

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