Summer into fall is the season for ornamental grasses to really shine in the landscape. They add texture, movement and often beautiful color or ornamental plumes to the late season garden. We get a lot of questions at Shorty’s about choosing the right ornamental grass for a particular spot and about care and maintenance to keep them looking their best.
Generally, ornamental grasses prefer moist well drained soil and full sun, but there are exceptions. Some prefer dryer conditions, and some can grow in boggy soil or as a pond marginal. Most do best in full sun, but there are a few true grasses and look-alikes that prefer morning sun only or shadier conditions. All ornamental grasses should get a good haircut every year to keep them looking their best, even the evergreen varieties. I like to do this in the late winter/early spring for all my grasses. When cutting back in spring, be careful to only go down to just above where you see new growth occurring. Deciduous grasses cut back during the dormant season should be cut to somewhere between 4-12” above ground level depending on the mature size of the grass. Once established, most ornamental grasses are quite drought tolerant, are bothered by very few pests and need little to no added fertilizer As a bonus, many varieties like Miscanthus and Pennisetum are deer and rabbit resistant due to their sharp fronds.
Now we’ll dive into some of our favorites and the best way to use them in the landscape:
Evergreen Varieties for Year-Round Interest
All Carex varieties (Sedge) are evergreen. These tend to be low mounding grasses (1-2’ tall) that do best in full sun with moist, well drained soil. Sedges come in a variety of colors, textures and variegation patterns, and do equally well in containers as they do in the landscape. A couple of our favorites are Carex testacea (Orange Sedge) which gets brilliant orange tips in the fall and Carex ‘Evercolor Everillo’ with its bright chartreuse color and graceful habit. Carex obnupta is a native variety that loves wet boggy conditions. Another excellent evergreen grass, Acorus (Japanese Sweet Flag), works well in wet areas and shadier locations.
Two favorite tough evergreen grasses that provide excellent blue color are Blue Fescue and Blue Oat Grass. These both prefer full sun and are very drought tolerant once established.
Pampas Grass, with its extremely showy plumes, is really the only large evergreen grass option for our area. This grass can easily exceed 8’ tall and equally as wide. It prefers very well drained soil. It is critical to cut Pampas grass back in early Spring to remove ratty overwintered foliage and promote fresh new growth each year.
Liriope (Lilyturf), Black Mondo Grass and Rushes/Reeds are a few look-alikes that are also evergreen. Liriope and Black Mondo Grass spread making them a useful groundcover or border edging. Rushes and Reeds like Juncus ‘Blue Arrows,’ prefer very wet soils and can grow as pond marginals and are often used in rain gardens or bioswales.
One of our favorites for the shade garden is Hakonechloa or Japanese Forest Grass. This is a beautifully textured grass that moves gracefully in a light breeze and is not bothered by deer or rabbits. Hakonechloa ‘Aureola’ has variegated golden foliage that really brightens up a shady area. As mentioned above, Liriope, Black Mondo Grass and Acorus also do well with morning sun and afternoon shade.
Best Showy Plumes or Seed Heads
Although Pampas Grass plumes can be hard to beat, not everyone wants a grass this large, and it doesn’t always perform well in the PNW. Miscanthus varieties like ‘Gracilimus’ and ‘Yaku Jima’ have graceful feathery plumes that sway in the late summer garden. If you want a tall but narrow grass with showy plumes, Calamagrostis ‘Karl Forester’ is the best choice.
Hardy Pennisetum (Fountain Grass) varieties like ‘Hameln,’ ‘Burgundy Bunny,’ and ‘Ginger Love’ have showy bunny tail like plumes and are better for smaller spaces. Another grass that deserves mention for its striking seed heads is Bouteloua ‘Blonde Ambition.’ These varieties all prefer full sun and are very drought tolerant once established.
It’s hard to beat Japanese Blood Grass for color, but there are other excellent options as well. Another favorite in the nursery right now is Schizachyrium ‘Standing Ovation.’ This variety of Little Bluestem Grass has beautiful blueish fronds tipped with purple. Pennisetum ‘Burgundy Bunny’ has reddish bronze fronds all summer long, and Carex testacea (Orange Sedge) has brilliant orange tips in the late summer/fall. Many other ornamental grasses turn shades of reddish/bronze in the fall as they begin going dormant. And of course, there’s the look-alike Black Mondo Grass which is one of the most dramatic.
There are also a couple of non-hardy ornamental grasses that are worth planting every year in my opinion! Both Purple Fountain Grass and Pennisetum ‘Black Stockings’ will provide high drama by late summer even when planted this late in the season. Phormium, or New Zealand Flax, is another look-alike that loves hot sunny conditions and can add instant tropical or desert appeal to the landscape or container depending on its planting companions.
Ornamental grasses deserve a spot (or several 😊) in everyone’s landscape and there is a suitable one for just about every niche and gardening aesthetic.