Pruning Ornamental Grasses

by Anthonyfamilyinfo@gmail.com

Ornamental grasses are grown primarily for their foliage rather than their flowers which are known as inflorescence. Most are perennial and valuable landscape plants that add texture, form and motion to the garden. Some are true grasses, either native or introduced species, but included in this group are sedges and some grass-like plants.   

Should ornamental grasses be cut down in the fall or spring?

Many of these grasses are perennial so their foliage is killed by a freeze. The dead foliage needs to be removed before new growth begins in spring. Cutting back grasses increases exposure to sunlight and stimulates new growth. 

In central Texas, this maintenance is commonly done in late winter or very early spring. In keeping with a more naturalized and ecofriendly landscape, grasses are left through most of the winter. The dead foliage adds interest, provides food for wildlife and is a protective habitat for pollinators and other beneficial insects.  

Most all ornamental grasses need to be cut back to thrive. However, some sedges require combing or removal of only the dead foliage. Many ornamental grasses grow quite large, so it can be a big maintenance job that gets messy. However, the process is pretty straightforward. 

When should you cut back grasses?

Cut them back before the new shoots grow or you will cut off the new growth and leaf tips. In areas where wildfire is a concern, cut grasses back after a freeze and foliage browns.

Handy Tools

Helpful tools to prune ornamental grasses are hedge trimmers, gloves, hand pruners, a rake, string, cord, tape or power hedge trimmers.

How far do I cut back ornamental grasses?

Cut these grasses back to within a few inches of the ground. How much is a few inches? Probably 6 or so inches and no worries, grasses can take it and will grow back strong.  

Before cutting, gather the leaves and tie the stalks up in a bundle with string, a bungy cord or even tape. This keeps the debris contained and makes for an easier and quick cut back. For especially tall or bushy grasses like fountain grass, you may need to tie a couple places. If the grass clump is large, you might tie it in 2 to 3 sections. 

Now it is time to cut. I use an electric hedge trimmer for large, thick grasses like muhly grass and panicums. It is a fast and clean cut. Then I tidy up the stubs with hand pruners and rake. For small grasses like Mexican feather grass (Nasella tenuissima) I use hand pruners.  

What to do with the dead foliage? I have actually chopped up the stalks and used as mulch for my winter potato and onion crops, but it can go into the compost pile, too.

The last thing I do is fertilize with compost around the grass and mulch the ground surface. That’s all the maintenance that ornamental grasses need.

Growing tip – how do you maintain ornamental grass?

Ornamental grasses need to be divided every 3 to 4 years. The easiest time to do this is when you are doing late winter or early spring pruning. You will know the grass needs dividing when you see a dead area in the center and living grass at the outer edges. 

Use a sharp shovel to dig up the grass. Compost the dead center, then divide out the living edges into pieces that are not less than 4×4 inches. A small saw may be required for cutting. Replant the divisions immediately or they can be potted up, planted later or given away.

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