The last bastion of prunable perennials in my gardens are the ornamental grasses. I’ve noticed in Austin that many landscape companies prune ornamental grasses earlier in winter, but the little nubs of grass left are unattractive–they remind me of alien pods. (Not that I’ve seen many alien pods.) Grasses don’t flush with new growth until late February or early March and winter-tinged grasses are lovely specimens. During winter dormancy, ornamental grasses develop a toasty color and the graceful forms lend elegance and interest to any landscape.
I’m especially fond of the native Big Muhly (Muhlenbergia lindeimeri). These larger grasses move gracefully in winter winds.
Though, I guess I could have raked the leaves from this one in the back garden.
Once I detect discernible green shoots emerging, that’s when I prune.
I prune to a ball/oval shape, but I’ve also seen these grasses pruned flush to the ground. I’ve even seen them pruned as boxes, though that doesn’t appeal to me and the natural form of the mature plant is round, so pruning as a square is weird and antithetical to the form of the plant.
Ready for new growth!
This non-native (to Texas) Maiden Grass (Miscanthus sinensis),
has been a fine addition to my gardens–I wish I had space for more of them. It’s been a great performer all year, but who could prune these fabulous seed heads early in the winter?
But, it’s time for spring growth, so off with their heads!
I transplanted my three Gulf Muhly (Muhlenbergia capillaris) in November. I don’t have a great spot for these grasses because my gardens are full-sun challenged and Gulf Muhly perform best in blasting sun.
I’ve pruned for the new growth,
and have hopes that this spot will provide the correct amount of sun for these native beauties.
Bamboo Muhly (Muhlenbergia dumosa) is native to New Mexico/Arizona and is an airy, light green grass during the growing season. During winter dormancy, the foliage is tawny beige, though it holds its feathery plumage. When completely dormant, Bamboo Muhly benefits from shearing to its clump.
In my gardens, two of the Bamboo Muhly didn’t become completely dormant, so I decided to selectively prune only the cold damaged foliage.
However, one plant had no green growth, so I sheared it to the ground.
And now it’s ready for new spring growth!
Mexican Feathergrass (Nasella tenuisima) is beautiful year round as a single specimen,
or in groups.
It is NOT however, a plant pruned by shearing foliage like the four discussed above. If you do this in the winter:
You will not get this in the spring.
NO. NO. NO. Never, ever do that!! It will take MONTHS to recover and will look stupid in the interim. I sacrificed a seedling to demonstrate this abhorrence, but I see this all over Austin.
The method for “pruning” Mexican Feathergrass is to gently pull off the dead foliage which by late winter is a light brown/tan color.
Hold down the center of the plant and gently tug the dead grass or run your fingers through the foliage, in small bits, until it pulls free of the main plant. It will come out easily and if it doesn’t, don’t force it. I’m not coordinated enough to photograph that action, but you’ll end with a handful of grass pulled out.
As you’re pulling out the dead foliage, hold the mother plant down with the other hand, otherwise, especially in older plants, you’ll pull the up the entire plant. Which I’ve done. Numerous times. If that happens, swear a little, (you’ll feel better), then re-plant a new seedling and start over again.
For me, pruning ornamental grasses means the end of winter and is the gateway to spring abundance and a long growing season.
It’s done. Happy Spring!
My Gardener Says... 
Great tutorial Tina! I also prune muhly somewhat late and this year a few had their tips cut off but they’ll get over it. Your tips on bamboo muhly are especially helpful since I haven’t had to cut them back until this year.
Maybe this will be the year you get full bloom from your gulf muhly grasses.
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Hi Shirley and thanks! Is it cold in SA?? It’s sooo cold here! so much for spring. I’ve done it both ways on the bamboo muhly–pruned completely and not so much and I haven’t seen a huge difference in growth. None of mine are in full sun though, so that might make a difference.
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We have been hovering in the mid-30s for hours and are looking at a hard freeze overnight. Most of my perennials have sprouted so it’s a concern.
My bamboo muhly are also part shade and the protection usually keeps them from frost burn but not this year.
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Sending warm thoughts to your gardens, Shirley. I covered a bunch of stuff, which I never do, including some opened iris blooms. I don’t ever recall this hard of a freeze once blooms have happened. Sniff.
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Good tips on pruning ornamental grasses. Like you, I cringe to see fall-blooming grasses cut back in early winter — or even fall. They look great all winter, so they really shouldn’t be cut until just before spring growth starts.
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I hate those nubs. I guess the reasoning is that the landscape companies have so much to do, they prune early and often, but to cut something that looks so great during winter is a shame.
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Thanks for the tips. I’ve tried it both ways with the wire grass and you are right – if you want a full display you only want to – carefully – thin out the dead stalks. I didn’t kill the plants I accidentally clipped back the first year I had them (well before your tutorial unfortunately) but I sure enough discouraged them. And that is another good reminder to hold the plant down with one hand to avoid accidental transplants.
I read someplace that leaving the grass seed heads tall during the winter provides needed protection for certain moths and butterflies. Gorgeous display – protection for the pollinators – win/win!
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Hi Deb! I also didn’t kill the Mexican feathergrass when I sheared it, but it doesn’t have that glorious spring show. I learned the hard way. I hadn’t read that specifically about the protection for pollinators, but it doesn’t surprise me. I hope your garden fared well after last night’s freeze. I might have finally lost some stuff for this winter. Argh!!!
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I have lots of Mexican feather grass. I bought a cheap, plastic wide-tooth comb, the biggest I could find, and literally “comb” my feather grasses to remove the brown bits. Works great.
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Hi Sandy, thanks for stopping by. What a great idea–thanks for the suggestion, I’ll have to try that.
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Grasses are one of the few plants that I prefer during their dormancy with their seed heads prominently displayed. I love looking out at an un-mowed prairie of native grasses all golden and moving with the breeze. I’m still hoping to duplicate this look in my own garden some day.
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I agree and I hope that you’ll be able to do that on your property! Post pics and story when that happens, Ally.
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Hi Tina, Thanks for all these great tips. I had a quick question about multiple mexican feather grass plants that have just started to sprout up. I’d like to move some of them to another area of the garden but wondered if I should wait until they are a certain size before attempting to transplant. Any guidance would be appreciated! -Sally
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Hi Sally! I usually transplant when the seedlings are roughly the size you’d see in a purchased 4 inch pot, that is a plant about 5-6 inches tall. I personally like to transplant before a rain, if possible. The most successful transplants for me have been when I have some soil attached to the root system. Water for a week or two, every few days, then you can back off on that. I’ve found that the feathergrass transplants quite well–I hope that helps!
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