Pruning Miscanthus Grass: How to Cut Back Big Ornamental Grasses

How to prune Miscanthus and other large, dormant ornamental grasses.

Ready to prune your Miscanthus Grass? This is the time of year to do it! Ornamental grasses start shedding little grass bits everywhere in January, and with every windy storm they become increasingly messy until in early March you have a bunch of grass sticks still upright and grass leaves piled up everywhere in your garden BUT on your plant!

You also want to prune now because if you wait too long, the new growth will begin to emerge from the base and when you whack the old growth, you’ll also trim the new shoots, which is no good.

I’ve written before about how to prune ornamental grasses – which ones you ought to whack and how, and which you ought to leave be. The Miscanthus grasses are pretty much all in the “whack” category, except for M. transmorrisonensis, the Evergreen Miscanthus that still looks green and fresh in winter. You needn’t prune that one!

Here’s a quick tutorial on how I prune Miscanthus Grass in winter:

Dormant Miscanthus grass before cutting back

The “before” shot. It’s very pretty, but what you can’t see are all the grassy leaves that have piled up around the neighboring shrubs. Mes-sy!

Dormant Miscanthus ornamental grass tied up in preparation for pruning

First, I use some rope to tie up my Miscanthus Grass so the stems and leaves don’t fly every which way when I start to cut.

Miscanthus grass after pruning to 6 to 10 inches tall

Once the grass is neatly tied together, I use my trusty Fiskars Hedging Shears (video review here) to cut the entire thing back to 6 to 10 inches tall.

The Fiskars Powergear Shears cut thicker stems than most handheld hedging shears do (most hedgers are just meant for delicate leafy growth like Boxwood), so they’re great for cutting things back at this time of year.

You could also use electric or gas hedgers, but doing it by hand is safer and takes little time, so using the power hedgers isn’t a huge time-saver. It’s really the fine-tuning and cleanup that is more time-consuming!

Once it’s cut, you can lift the entire bundle of grass and take it to your compost pile. Simple, no?

Related reading:

How to prune other types of ornamental grasses in winter.

If you’re tired of cutting your grasses back every year, here are my suggestions for some winter-interest grasses that don’t need pruning.

How to summer-prune your Miscanthus grass.

16 responses to “Pruning Miscanthus Grass: How to Cut Back Big Ornamental Grasses”

  1. That is brilliant. We have a tall pampas grass, Cortaderia selloana, in the garden that I am getting ready to trim. I think I have been avoiding it because of the saw like margins on the leave blades. This tip will come in handy. Thank!
    .-= Matti´s last blog ..Avenue of the Giants =-.

    • ICK! I just removed three of those from a garden the other day – so invasive! Honestly the leaf blades are terrible but I did not feel a thing when pruning – I used my mud glove-style gloves that are dipped in rubber and wore a hoodie and didn’t get “bit” by them at all. I did bruise my hands hacking the damn things out though.

      If you’re just trimming it should go pretty smoothly… My Fiskars Powergear Shears that I love cut through the blades and stems like it was nothing.

  2. I use the tying technique on almost all tall unwieldy grasses I trim. Works a treat! However, I tend to use my electric pruning shears, instead of manual ones, though appreciate the tactic of using manual tools. 🙂

  3. Nice post. This is the time of year I usually take the Felcos to any ratty looking Sword ferns, that is before their fiddleheads begin to appear and unfurl. It’s been such a mild winter, that they are perfectly healthy and green and don’t require pruning. Check that off my list!
    .-= tom | tall clover farm´s last blog ..In the Mail a Memory Is Sent =-.

  4. I can’t stand it when people wait too long to prune miscanthus… or salvias! When I see it over grown, driving through neighborhoods, I just want to jump out of my truck and run over to cut them down. I figured that wouldn’t look to sane though.

  5. Aww, Monica, I’d use a power hedger too, but I eat through those suckers so fast with my hand shears, it’s no big deal to do it with my Fiskars…

    Tom – same here!! I use the same tactic of Sword Ferns that are of mature size – but they are looking rather pretty right now…

    Dirty Girl (I love your name), I am so with you. SO straggly and unkempt-looking when left too long… Ick!

    Germi – all’s I gotta say is I am glad I’m not your Barbie, girl. My long locks would be gone in the blink of an eye!!

  6. I pruned mine like this last year and the new growth came in very sparsely. One batch had just a few blades of new grasses. You don’t need to pull out old reeds?

    • Possible issues – either you pruned too late and nipped off the new growth, or your miscanthus is huge and needs dividing. Perhaps you pruned too low and should prune higher up next year – your grass may have developed a taller core? Or it could be having health issues due to shade or lack of drainage.

  7. What is best technique to reduce the footprint of these grasses? Am I required to dig out the roots? Mine are too large with a foot print circumference if several feet, trimming is a majot chorse and they are too large! Thanks

  8. Can these be pruned in the fall as well? With a new house we inherited an already overgrown miscanthus that is falling over and it’s only September. Can we do it now or better to wait till winter?