Ornamental grasses are eye-catching, low-maintenance additions to home landscapes that offer color, texture and seasonal interest, but they continue to be underutilized. To share the many benefits of growing and using ornamental grasses, my guest this week is horticulturist, lifelong gardener and author Brie Arthur.
Brie has written two books on gardening, “The Foodscape Revolution” and “Gardening with Grains,” both of which include tips on using grasses in the garden for visual interest as well as for edible crops.
Brie studied landscape design and horticulture at Purdue University in Indiana and has worked as a propagator and grower at leading nurseries. She is currently the president of the International Plant Propagators Society, Southern Region and sits on the board of the North Carolina Botanical Garden Foundation. As a garden communicator, Brie works with garden clubs, extension services, universities, landscapers and trade organizations.
For everything you’ll need to know to select, grow and care for ornamental grasses and grass-like plants, you can receive my brand new free resource. Growing & Using Ornamental Grasses in the Home Landscape. You can also text GRASSGUIDE to 44222 to get a copy of the free guide.
Why Ornamental Grasses Are Underutilized
While ornamental grasses have risen in popularity at botanical gardens and in public space and commercial landscaping, they lag behind in residential landscape design.
Brie notes that the main reason ornamental grasses are not widely used in residential gardens is that they have only been promoted in the landscaping industry for the last 25 or 30 years. Even though that sounds like a long time, grasses are still relatively new to the trade. Before recent decades, ornamental grasses and many other perennials were rarely spoken of. Instead, Brie says, there were annuals and there were shrubs — and that was it.
As knowledge increases, gardeners and landscape designers have become more receptive toward grasses, perennials and natives.
Top Reasons for Using Grasses
Brie says there is still a long way to go in educating the public on the benefits of using ornamental grasses. Fortunately, she is happy to share.
Grasses are translucent and light up wonderfully in low sun or under a full moon. They add color and texture to the garden and change with the seasons as they grow, mature and set seed. Some will flower for even more color.
It’s now widely promoted to leave grasses up over the winter, rather than cutting them down in fall, Brie says, so they can continue to provide visual interest even when they are dormant.
Additionally, watching — and even listening — to grass sway in the wind is another reason to appreciate ornamental grasses. Grasses are one of the few plants that add movement to the garden, and the seed heads really come to life as they stir in the wind.
There are native varieties of grass that will fit the bill for every particular environment that you have, so there’s really no place in your landscape that you can’t include an ornamental grass, Brie says.
Ornamental grasses are very well-suited for difficult soils, she notes. North American native grasses from prairies, for instance, are used to growing in hard-pan clay in dry conditions
Grasses run the gamut from varieties that are accustomed to growing in the blazing desert sun to those that grow in dense shade.
Ornamental grasses also come in a wide variety of heights. The tallest grasses can be used for screening or to delineate borders. And unlike some border plants that can grow too big and cost thousands of dollars to remove, such as evergreens, Brie says, grasses are capped at a maximum height and are not expensive to remove.
You will never find a plant that needs less care than an ornamental grass, Brie says. In fact, the more you do to the plants, the worse off the grasses will be.
Once established, ornamental grasses do not require supplemental watering. They do not need fertilizer either, especially deep-rooted grasses that efficiently draw nutrients up to the surface.
Few plants love to grow on a slope as much as ornamental grasses do. The roots reach down into the soil, anchoring the plants but also knitting the earth together, preventing erosion.
Benefits to the ecosystem
Making the switch from needy plants to native grasses will reduce your landscape’s resource requirements — since natives do not require fertilizer and constant watering — and the switch also means no more applications of potentially harmful pest and disease controls.
Grasses also provide valuable habitat for native bees and other beneficial insects, and birds use old grass foliage to make nests with. Certain grasses are also masterful at carbon sequestration, such as prairie grasses that have root systems that can grow to be 8 to 14 feet deep.
Using a variety of grass genera and species, rather than a monoculture of grass like a turf lawn, increases biodiversity. “Diversity is the solution to so many of the problems that we humans have created,” Brie says.
Loving Ornamental Grasses and Learning Lessons
Brie says she’s been having a love affair with ornamental grasses her whole life. She grew up in the Midwest and remembers the incredible collection of various species of grasses that occur naturally near woodlines.
As a teenager in Michigan, she would read books by landscape designer Rosalind Creasy, who specializes in environmentally friendly plantings, and was inspired to redesign her family’s own landscape with ornamental grasses that would not require regular shearing. She planted Calamagrostis “Karl Foerster” (a.k.a. feather reed grass) but also some of the ornamental grasses that were the earliest to the market and proved problematic.
Miscanthus sinensis (Chinese silvergrass) is an ornamental grass that produces seeds that grow in disturbed areas, displacing native grasses and creating a fire hazard when the foliage is dead and dry. In the Southeast, especially in North Carolina or Georgia, Miscanthus sinensis has naturalized in many places, giving native plants fewer opportunities to grow where they should.
Another example of an invasive grass is Imperata cylindrica, which is often called blood grass or cogon grass. It’s a running grass that has been banned in a number of Southern states because of its aggressive spread via both rhizomes and seeds, affecting both fields and forests.
But since the 1990s, horticulturists and nurseries have learned a lot. We know now to choose native ornamental grasses that will not cause ecological damage if they escape our landscapes, or to plant hybrid cultivars that do not produce viable seed, such as Calamagrostis “Karl Foerster,” which is sterile.
When Brie looked to plant something at her current home in North Carolina among small trees, she decided in ornamental grasses. This time, she chose Muhlenbergia capillaris (pink muhly grass) and Panicum verbatim (switchgrass). In the fall, she planted a pattern using long, skinny landscape plugs, which are easier to plant and more economical than mature plants.
Unfortunately, Brie only got one season out of the plants. Her region experienced an exceptionally wet year and the ground became saturated. All of her muhly grass — which does not like wet feet, particularly during winter dormancy — died.
This was a learning opportunity for Brie. It dawned on her that she was trying to grow on flat ground the same plants that she saw thrive in areas along highways with a 45-degree grade. Those plants on slopes never sit in standing water. Her takeaways from the experience were to make her planting beds higher and to choose plants that are more tolerant of seasonal wetness.
Choosing Ornamental Grasses for Your Landscape
Consider which way the sun rises over your property and how much sun different spots receive. There will be a grass suited to each type of exposure, from all-day sun to dense shade.
When picking the right grass for the right spot, also consider the scale: There are all different sizes to choose from.
You can accent your border plantings, such as hollies or azaleas, with clumps of medium height or tall grasses. For example, Panicum, the native switchgrass, will be 3 feet tall once it goes into flower, while Andropogon gerardii, known as big bluestem, grows to between 6 and 8 feet tall.
Along the edges of planting beds — something smaller is called for. To that end, there are a number of grass-like ornamentals that don’t get large at all — such as Liriope (lily turf), Carex (sedge), and Acorus (sweet flag) — that offer the same benefits as true grasses, which are in the Poaceae family.
Many grass-like ornamentals are also evergreen, depending on the region where they are grown, and Carex and Acorus are both tolerant of shade and damp conditions. Acorus is also hardy in zones 5-10, so it can thrive in most wet places.
Acorus gramineus, known as Japanese sweet flag or grassy-leaved sweet flag, has a number of varieties — and Brie recommends getting them all! She likes to use them to define edges, or in containers, which don’t even need drainage holes because the plants can survive in standing water. A few highlights are:
- A. gramineus “Variegatus” – This variety is deep green and variegated with white.
- A. gramineus “Ogon” – This variety has bright chartreuse leaves.
- A. gramineus “Minimus Aureus” – This is the dwarf golden variegated sweet flag with a mat of bright green and gold that looks like lawn. Brie likes it for window boxes and notes that it is great for wet conditions and dense shade.
What to Do When Planting Ornamental Grasses
An ornamental grass at a nursery has been irrigated regularly while growing in a well-drained potting medium with slow-release fertilizer. As Brie says, it hasn’t had to try. Before sticking it in the ground, take a few steps to improve its chances for success.
After removing the plant from the nursery pot, rough up the roots well. Breaking up the root ball will encourage the roots to grow into and acclimate to the native soil rather than just winding back around themselves and staying put in the potting mix.
Fertilizer or compost should not be added to the planting hole, because, again, the roots will want to stay in that hole instead of reaching out to find water and nutrients. If the roots stay compact, it hurts the grass’s chances of survival.
But do be conscious of the soil pH. If the pH level is outside of a grass’s ideal conditions, it can negatively affect the plant’s ability to take up nutrients. A soil test will tell you if you need to amend your soil to raise or lower the pH, to make it either more basic or more acidic. Alternatively, choose native grasses that are already suited to the local soil. This is easier and less costly than monitoring and adjusting pH.
Why And How to Cut Ornamental Grass
True grasses should be cut back annually to remove dead foliage and welcome new growth. (Evergreen grass-like plants should never be cut back.)
A sign that it’s time to cut an ornamental grass is when you see new growth begin at the base. At that point, it’s safe to cut back the previous year’s growth to 8 to 12 inches tall.
Landscapers will tend to shear grasses in the fall after one frost and then take away everything they cut off — all that good organic matter. Brie points out that this can be problematic because many grasses have hollow stems that will collect water all winter and potentially rot. She recommends waiting until spring to cut, which also allows you to enjoy the foliage all winter. Even if the top of the grass has browned and died, it will continue to provide visual interest.
Grasses that are native to Midwest prairies actually regrow better if they have been burned down rather than cut down, Brie says. This could result in your neighbors calling the fire department, so if you do decide on this method, be extremely careful. Brie is planning to burn some of her grasses this year with a torch in one hand and a hose in the other.
If you are cutting, layering the cut foliage someplace in your landscape where it will be out of your way can provide valuable habitat for beneficial insects and other creatures. “You’ll be amazed at how much life ends up taking advantage of that,” Brie says.
Why and When to Divide Ornamental Grasses
Perennial clumping grasses, which most ornamental grasses are, should be divided every few years so that they continue to look their best. If they are never divided, the center of the plants will form an unattractive dead spot. As Brie puts it, they turn into a doughnut.
Brie says to avoid dividing ornamental grasses when they are dormant. Cutting up a plant during dormancy can stimulate growth at the wrong time of year. That new growth will be vulnerable and may be damaged by frost or excessive heat.
When a plant is actively growing is the best time for propagating most plants, Brie notes.
She recommends making ornamental grass divisions in mid-spring, when most grasses will be actively growing. Grasses should be dug up and split two, three, four or more ways with a sharp spade. However, digging out the entire clump of a well-rooted grass is labor intensive. Brie says you can also cut out a division from the outer edge of a clump rather than digging up the whole plant.
Dividing is important for the long-term management of ornamental grasses and it also provides you with more plants — for free!
Grains as Ornamental Grasses
The same annual cereal grains that farmers grow for food can be used by gardeners are ornamental plantings.
Cereal grains can be appreciated for their own beauty for many months, and after they set seed they will attract and feed birds, Alternatively, you can harvest the grain for your own use, taking pleasure in knowing that it is pesticide-free and your food miles have been reduced to zero.
Many cereal grains love growing in wet soil, which is perfect for Brie’s Southeast growing conditions, and they provide the same visual interest as ornamental grasses.
The biggest difference when using grains in place of perennial grasses is that they will die each year and will need to be reseeded. Alternatively, if you practice crop rotation, you can grow a different annual edible crop in the same spot the following year.
Grains have a symbiotic relationship with microbes in the soil that will improve soil fertility and growing conditions. Their deep roots act as tillers, aerating dense soil while also drawing up nutrients. These traits make grains an excellent cover crop.
When grains are spent, they can be turned in, which is the practice of mowing the grains and then working the cut foliage and the roots back into the soil, where microbes will digest the organic matter, improving soil fertility and tilth. Bries says this concept of “composting in place” has totally transformed how she gardens.
Grains can be grown to enrich the soil in lieu of bringing in outside material, such as fertilizer or compost of unknown origin.
Questionable compost may contain weed seeds or, even worse, persistent herbicides that will kill or stunt the growth of broadleaf plants. This is a big problem stemming from grains and other grasses that are sprayed with herbicides and then fed to horses. The herbicides will remain for years even in composted manure from those horses.
If you haven’t listened yet to my conversation with Brie Arthur, you can do so by scrolling up the page and clicking the Play button in the green bar.
My New Comprehensive Guide on Ornamental Grasses
If you are ready to learn everything you need to know to select, grow and care for ornamental grasses, you can request my new free resource: Growing & Using Ornamental Grasses in the Home Landscape.
The guide offers a comprehensive look at grasses and grass-like plants and will help you identify the right plants for your region and where they will fit in your landscape.
You can also text GRASSGUIDE to 44222 to secure your copy.
What ornamental grasses are growing in your landscape? Share with us in the comments below.
Links & Resources
Some product links in this guide are affiliate links. See full disclosure below.
joegardener free resource: Growing & Using Ornamental Grasses in the Home Landscape.
joegardener Online Gardening Academy™: Three popular courses on gardening fundamentals; managing pests, diseases & weeds; and seed starting!
joegardener Online Gardening Academy Essential Gardening Fundamentals: The basics on healthy soil, planting, watering techniques, composting, raised bed and other gardening methods, fertilizer, the many benefits of mulch, and more.
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