How to Prune Cool-Season Grasses

How to prune cool-season grasses involves timing, tools, and clean-up. Karl Foerster Feather Reed Grass, Calamagrostis acutiflora is a cool-season grass since it likes to grow before temperatures exceed 75°. In our hardiness zone, 7a, here in Chelan, Washington, our cool season is March through May. The best time to prune cool-season grass is at the beginning of the cool season.


Now that we’re into March, it’s time to prune and remove last year’s growth so that these grasses can feel the sun’s heat and maximize their growth period between March and May.


Now that we know the time is nigh, let’s discuss the equipment. Here is my equipment for doing the pruning of my older established grasses. I have gloves, a power hedger, gardening tie tape, and an electrical cord for my power hedger. These are my favorite tools, and I can explain. I have learned the hard way that gloves are essential. The wicked blades of mature grasses are sharp! To prune the grass, if you want to have sculpted shoulder and arm muscles, pruning loppers are adequate. I, on the other hand, prefer powerful machinery.

My quest for a powerful machine to prune grasses began with an electric Black and Decker hedger (the one in the picture above). After a few hedging jobs, I found the extension cord troublesome. So researching my options further, I moved to a battery-operated Black and Decker hedger. Quickly I realized the big, dense grass blades would run the hedger’s batteries down fast. And then the continual need to recharge the batteries became a bigger problem, so I’ve returned to the original electric hedger with its electric extension cord. The good news is that while your grasses are young, tender, and small, hand pruners or scissors work fine.

Bundling the grass makes the job with the power hedger more efficient. I want to leave 1/3 of the plant in place after pruning, so I wrap the tape around the grass and tie; then, I cut the grass just above the tape. As you may note in the video, using this method involves just one quick swipe with the power hedger.


Bam! Done! Now it’s time to pick up the debris. May I suggest another tool? This makes all my gardening clean-up easier. These professional reusable garden waste bags make the clean-up easy with minimal additional weight.

All the effort is worth the trouble. Now that you know how to prune your cool-season grasses, you can celebrate by choosing how you want to go about it. Will you hire out the job? Will you research and purchase the best DIY hand tools or power tools? So many choices, but one thing is for sure, now is the time to get it done for the best cool-season grass growth.