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.
But wait!
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 Not To Prune
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!
Movement, Winter Interest & Wildlife Value
Leave your Ornamental Grasses standing in your landscape to create movement and interest during the fall and winter months! The plumes add texture and something to look at throughout the show, while many varieties feed songbirds. The grassy clumps even offer shelter to wildlife and birds, and allow beneficial insects places to overwinter!
So for these reasons, hold off cutting your grasses until spring just before they start to grow in the spring!
Free Insulation and Protection!
Keeping the tan foliage and plumes intact also protects the crowns from the winter chill and damage, reduces frost heave, and insulates their surrounding root systems like mulch.
Cutting back your grasses in the fall can also allow water to get to the crowns and can cause them to rot.
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.
Potential Disease Issues
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.
Spreading/Self-Seeding
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.
To Decorate Indoors and Out
Lastly, go ahead and prune your Ornamental Grass plumes for your fall and winter décor indoors and out! The showy seedheads are great additions to dried arrangements, swags, outdoor containers, and interior design!
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.
How To Prune Ornamental Grasses
Grass blades can have serrated edges and their tissues contain high amounts of silica which quickly dulls your garden tools and may even scratch you. So be ready when tackling this pruning task!
- Sharp garden shears or pruning shears
- Coarse toothed folding saw
- Or an electric hedge trimmer or weed wacker
- A Rake
- Bagged Mulch
- Twine or bungee cords to hold the bunches together
- Yard waste bags
- Long-sleeved shirt, boots, and thick gloves
Tie together the leaves and stems for easier cutting and disposal using strong twine or a bungee cord. Using your tools of choice, cut back the clump evenly to a height of about 4 to 6 inches. Dispose of the trimmed leaves and stems in your yard waste, and collect seedheads for your crafts!
Take the rake and clean out the crown of your Grass clump to eliminate excess debris and built-up clutter that accumulated throughout the year. Top-dress the root system around your grass with 3-4 inches of arborist mulch chips to keep the roots insulated all winter and hold in moisture.
If it is a dry winter or your autumn has been plagued with drought, water your Grass and other plants in well for the winter.
Winter-Ready Gorgeous Grasses!
Whenever possible, it’s best to hold off trimming Ornamental Grass until late winter or early spring before it starts to grow. They add too much beauty to the upcoming winter to make giving them a buzz cut worthwhile!
But when it is necessary, feel safe knowing you know how to prune Grasses correctly and for the right reason.
Nature Hills is here to help you keep all of your favorite landscaping ornamentals ready for winter and looking their best at all times of the year!
Happy Planting!
