Ornamental Grasses: Screening and a Four-Season Show!

Helpful Products from Gardens Alive!
Weed-Aside^™ Herbicidal Soap

Q. I want to grow a privacy screen. I can get Chinese Elm Hedge for a great price, but it's deciduous and I'm worried that it might not provide full privacy in the winter. The price for good Arborvitae is high, and I'm afraid I'd have to buy a thousand to arrange them in the zig-zag order you advise to achieve a healthy screen. Any suggestions? Thanks!

---Jeff in Drexel Hill, PA

A. Yeah—as the title of this Q of the Week suggests (more than suggests, actually), we're going to recommend ornamental grasses. But right now, I want to make a little detour into the first plant you mentioned, as it's a very interesting one. Chinese Elm Hedge is actually more of a tree that is easily trained into a very tight hedge. It can grow tall enough to tower over a home, yet regular pruning will keep it at any height you choose. It is technically deciduous, but many gardeners say that the branches become so thickly intertwined, it's still a pretty good screen in winter. The roots, however, can become aggressive when planted too close to pathways and structures and lift up paving and the like, so use common sense when deciding if the site is appropriate. Anyway, back to the questions....

Q. When we tilled to install a vegetable garden we discovered we had more rocks than dirt, and a lot of the dirt was clay. Our land is treeless, hot, barren and not very inviting. Do you have any suggestions on how to start creating a backyard that someone would actually want to spend time in? We need quick, cheap shade, color, etc.

----Sadie in Kunkletown, PA

The foundation plantings along the home I just purchased were ugly, intertwined with tall weeds, and overhung my walkway and steps—so I had them removed. I have always liked grasses. When I replant, could I use clumps of grasses instead of shrubs? I will gladly do the research as to which exact grasses would be most appropriate if you tell me it's a workable plan.

---Pat in Milford, DE

A. I think it's a great plan, Pat! And great for the guy who wants an inexpensive privacy screen and the one who wants to start landscaping that denuded backyard. Ornamental Grasses are perennial, come in all shapes and sizes—including heights appropriate for screening—grow fast, tolerate all kinds of soils and climes, have exceptionally dramatic four-season interest, and as acclaimed garden writer and natural landscape designer Rick Darke notes, they also move, make wonderful sounds and play great tricks with light.

And your offer to do local research is right on the money. There's a VERY wide range of grasses out there and you should see what your local nurseries and extension office recommend before you make your final choices. I'll discuss a few tall standouts for screening use right now; all are clumping grasses whose roots stay well behaved, and all will survive winter in their indicated USDA Zones. Again, there are lots of other types, including smaller specimens for those foundation plantings. This is just a sample of the best types for tall display:

Switch grass (Panicum virgatum). A Rick Darke favorite. Six feet tall, with blue-green to purple stems, adorned by foot and a half tall flower stalks. In the Fall, the leaves turn yellow; the flowers streak red and bronze. Rick especially especially likes the cultivars "Northwind" and "Cloud Nine." USDA Zones 5 – 10
Giant Miscanthus (Miscanthus x giganteus). Another Rick Darke pick. "Its a sterile hybrid", he notes, "and so it's plumes can't become a problem by spreading seed." Ten feet in height, spreading as wide as eight feet. Now that's a screening plant! (One website called it a "barricade".) Can develop foot and a half tall flower plumes following a hot summer. Survives in USDA Zones 5 – 9, but may not flower in Zones 5 thru 7. Can take wet soil, even somewhat salty conditions, but may need some help with the hose in really dry times.
Ravenna Grass (Saccharum ravennae): Nine feet in height, not counting the big feathery plumes on top that, for me, really define these garden wonders. Leaves go from grey-green to reddish bronze in fall. Zones 6 – 10.
Big Bluestem (Andropogon gerardii): For the native plant enthusiast, a prairie grass that grows in very tight and narrow six-foot high columns and whose blue-green stems turn red in the fall. Zones 4 –10, but Rick warns that it may get 'floppy' in some areas and when that happens, it stops being a good screen.
And maybe Giant Feather Grass (Stipa gigantea), whose seven-foot tall bright green clumps are adorned by dramatic flower spikes that add great winter interest, but whose stems are too light and airy for total screening, says Rick. USDA Zones 5 to 9.

Q. On a recent show, you advised a man looking for a visual screen to plant ornamental grasses and told him he did not need to cut off the seed plumes. When we were planning our garden, a local ornamental grass expert warned us NEVER to plant Maiden grasses, because invasive seedlings will take if you don't cut every plume off by December. So we planted beautiful zebra grasses instead. BUT we also planted one Maiden, and ten years later, we're still digging out seedlings. Please warn that gardener!

---Morgan in Aldan, PA

A. I don't have to, Morgan—you just did! Seriously, when we did a big feature on these grasses back when I was Editor of ORGANIC GARDENING magazine, we ran a caution that in some conditions some grasses can cross the line from ornament to weed. Clearly that happened with you.

So listeners be warned! I love those big plumes in the winter but on some plants and in some locales, letting them wave may be ill-advised. So do thorough research first. In addition to your local extension office, there are several excellent books on ornamental grasses by the afore-mentioned Rick Darke that will guide you well; he really knows his stuff. (Click on the 'Books by Rick Darke' link at his homepage for titles and details.)

Oh, and also make sure that the ornamental grass you choose is a clumping variety, like those we've named. Some others—like Giant Reed Grass—are 'running' types that will spread like the notorious arrow bamboo unless they're contained by an underground root barrier!

Ask Mike A Question Mike's YBYG Archives Find YBYG Show