It’s fall clean-up time and you may be eyeing your landscape in search of what to trim back next. That’s when the waving plumes of your Ornamental Grass may be what your gaze settles on.
Ornamental and tall native grasses are grown for their showy fall and winter interest, so put down those shears for now. Fall is generally not the best time to cut Ornamental Grasses down – Especially because they are just starting to really show their stuff!
So when is the best time? And what extenuating circumstances may arise that will warrant cutting back these stately plumes in the fall?
When planted correctly in well-drained soil that won’t become soggy over the winter, and in a full sun location, Ornamental Grasses have everything they need to stand tall all growing season and survive the brunt of what Ma Nature can throw at them!
Ornamental grasses add texture movement and unique beauty to any garden. Popular varieties like miscanthus, pennisetum, and schizachyrium come in a rainbow of foliage colors and provide year-round visual interest. When winter arrives, the dried foliage and seed heads persist, swaying gracefully in the wind. While ornamental grasses require minimal care, pruning is essential to keep them looking their best. This article will walk you through when and how to cut back ornamental grasses for healthy growth and maximum curb appeal.
When to Trim Ornamental Grasses
The timing for cutting back ornamental grasses depends on whether they are cool-season or warm-season varieties.
Cool-Season Grasses
Cut back cool-season grasses in early spring as soon as new growth begins to emerge. Popular cool-season grasses include blue oat grass tufted hair grass, and many types of fescue. Pruning too severely can damage cool-season grasses, so leave about one-third of the foliage in place when trimming in spring.
Warm-Season Grasses
Warm-season grasses can be cut back anytime between late fall and mid-spring. For best results, trim miscanthus, switch grass, and other warm-season varieties to within a few inches of the ground before new growth emerges in spring. Cutting warm-season grasses in fall gives a tidy look but spring pruning allows the foliage to provide winter interest.
How to Cut Back Ornamental Grasses
Follow these simple steps for cutting ornamental grasses cleanly and efficiently:
Gather Supplies
- Pruning shears, loppers, or hedge trimmers
- Raffia, twine, or rubber bands for tying grass bundles
- Rake for clearing clippings
- Wheelbarrow for hauling clippings (optional)
- Work gloves and eye protection
Tie Foliage in Bundles
Before cutting, gather stems together and tie them in bundles using raffia or twine. This keeps the foliage neat and upright for easier trimming. For large grasses, divide into smaller bundles.
Cut Back Foliage
Trim the bundles back to the desired height using sharp bypass pruners, loppers, or hedge trimmers. Remove any remaining loose foliage with hand pruners.
Dispose of Clippings
Place tied bundles directly into yard waste bags or a compost pile. Rake up any loose blades.
Extra Tips for Cutting Ornamental Grasses
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Wear protective gloves and eyewear – grass blades can be sharp.
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Use clean, sharpened tools for easiest cutting.
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Recycle grass bundles as mulch or add to the compost pile.
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Remove dead foliage from evergreen grasses like carex by combing it out with your fingers.
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For overgrown grasses, use a string trimmer or small chainsaw to cut back.
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Divide congested clumps every 2-3 years in early spring to promote vigor.
Properly cutting back ornamental grasses keeps them tidy and healthy while enhancing their graceful forms. Follow these guidelines for the best results. With just a little yearly maintenance, ornamental grasses will provide a beautiful, low-maintenance addition to gardens and landscapes for years to come.
Warm vs. Cool Season Grasses
Warm Season Grasses, planted in mild-winter climates can be trimmed back if you’d like in the autumn to keep them looking tidier and not have their leaves and large fluffy seed heads blowing around your landscape all winter.
For Grass and Sedges that are evergreen in those warmer climates – it is a good idea to gently rake/comb through the grassy leaves pulling or trimming out any old and brown foliage. Every few years it may be necessary to trim these plants down removing at least 2/3 of the old tops to give them a fresh start. This too should be done in spring before they start to grow.
Cool Season Grasses should only be pruned in the spring unless a disease issue is present or they were broken down from a summer storm or garden construction.
When To Go Ahead & Prune
Most Grasses are cut back to expose the crowns to sunlight and to eliminate a place for unwanted animals and insects to overwinter. Luckily this is rarely the case, and you can give the crowns their annual clean out in the spring. It is best to remove all of the old grass blades and flowering stems down to just a couple of inches each spring so the fresh new foliage can grow without the old dried foliage holding it back.
A good rule of thumb is that if any of your annuals or perennials (including Ornamental Perennial Grasses) have had some diseased foliage this year, then it is recommended to cut and remove all infected debris from the site. Prevent most of your issues by planting your grasses where the soil is well-drained to keep them healthy.
Dispose of them at your local yard waste site to prevent the disease from overwintering on last year’s foliage or spreading potentially to other plants.
Another reason for some Ornamental Grasses to warrant being trimmed in autumn is if they are the type that may self-seed and make themselves a nuisance elsewhere. Nature Hills uses Plant Sentry to ensure you won’t receive a plant that may cause trouble in your area in the first place, but sometimes you buy a home with something prolific already there, so pruning off the seedheads before the seed matures to prevent spreading.
The BEST Way to Prune Ornamental Grasses
FAQ
Should ornamental grasses be cut back?
Yes, ornamental grasses should be cut back, typically in late winter or early spring before new growth emerges. Cutting them back helps remove old, dead foliage, promotes fresh growth, and prevents the build-up of debris.
What is the best tool for cutting ornamental grasses?
The best tool for the job is a garden mini scythe but alternatively, you can use a sharp serrated bread knife. The key is in grabbing the grass like a ponytail and then cutting through the bottom of the stems quickly and efficiently. Think Uma Thurman against the Crazy 88 in Kill Bill.
What is the lifespan of an ornamental grass?
Ornamental grasses have a lifespan ranging from 3 to 10 years, influenced by species and growing conditions. Many are perennials, thriving for several years, while some are shorter-lived annuals.
Can I use a hedge trimmer to cut ornamental grass?
Hedge trimmers have taken the work out of cutting back ornamental grasses. Every garden design needs a few ornamental grasses, but cutting them back can be a lot of work without the proper garden tool. Electric, gas or battery operated hedge trimmers are important gardening tools to add to your spring clean-up tool.