Get It Growing for 03/13/26

Growing up, did you ever go out and get a fresh haircut before the start of a new school year? That ritual probably helped you feel a little more put together, ready to take on the tasks ahead.

In the garden, we’re on the cusp of a new season, too: spring! And for our ornamental perennial grasses, just like kids heading back to school, a haircut can do wonders to prepare them for what’s on the horizon.

Ornamental grasses are wonderful plants that add architectural elements and movement to landscapes. Many species go dormant and die back in the winter, and their leaves can get “burned” during freezes. By March, we need to help them out a bit and prune away some of that old, brown plant material to encourage spring growth — and to tidy the overall appearance of the garden.

Gulf Coast muhly grass (Muhlenbergia capillaris) is one of the most common ornamental grasses you’ll find in Louisiana landscapes. This native plant has long, thin, needlelike leaves and cloudlike, white or pink bloom clusters that appear in late summer and fall.

Right now, though, most muhly grass isn’t looking so great. So here’s what to do to clean it up: Get down on ground level and locate the base of the clump. Go up about one-third to one-half of the height of the plant, and that’s where you can make cuts to remove damaged, old foliage. You’ll end up with a neat, porcupine-like shape that will allow new leaves and bloom stalks to rise as the growing season progresses.

Avoid taking off more than half the plant. Unlike many other ornamental grasses we grow in Louisiana, muhly grass is semievergreen, meaning it continues to grow — albeit at a slower pace — through the colder months. Heavily pruning an actively growing plant can shock it.

Now, what about those other ornamental grasses — like reedgrass (Calamagrostis), maiden grass (Miscanthus), fountaingrass (Pennisetum) and switchgrass (Pancium)? These tend to die all the way back to the ground in winter, so we need to follow a different protocol for trimming them ahead of spring.

Periodically check on these grasses to see whether green shoots are emerging from the base of the plant. Once you see new growth, cut the entire clump back to within 6 inches of the ground.

A final word: If you cut back your ornamental grasses earlier, perhaps sometime in late January or February, don’t panic. This isn’t a totally uncommon practice, and your plants should be fine. We just recommend waiting until March because dormant clumps of grasses serve as valuable winter wildlife shelter, and holding off on pruning reduces the possibility of new flushes of growth being harmed by a surprise late-season freeze.

LSU AgCenter horticulturist Jason Stagg explains the different pruning strategies required by various ornamental grasses.

Cutting back ornamental grasses like this white muhly grass will help encourage spring growth. Photo by Olivia McClure/LSU AgCenter

LSU AgCenter horticulturist Jason Stagg prunes white muhly grass at the AgCenter Botanic Gardens at Burden. by Olivia McClure/LSU AgCenter

When pruning muhly grass, avoid removing more than one-third to one-half the height of the plant. Photo by Olivia McClure/LSU AgCenter

Muhly grass is semievergreen. Although plants mostly turn brown in winter, you’ll still see a few green, actively growing leaves in the clumps. Photo by Olivia McClure/LSU AgCenter

New growth begins to emerge from recently pruned pink muhly grass clumps in a parking lot in Baton Rouge. Photo by Olivia McClure/LSU AgCenter