For your Kentucky gardens, ornamental grasses are the way to go

Paul Cappiello

Special to Courier Journal

Feather Reed Grass is one of the most useful ornamental grasses for summer and winter impact and a better selection than invasive species such as commonly sold Maiden Hair Grass.

Back when I was a young landscape architecture student at Rutgers University in New Jersey, plant selection for the landscape trade was a little different than it is today.

The legendary Bruce “Doc” Hamilton — legendary for both his encyclopedic plant knowledge and for the ever-present Budweiser cans rattling around in the back of his pick-up truck — taught the full-year course that covered everything from Acer (maple) to Zinnia — four hours of lecture a week and three hours of lab out walking around campus through two full semesters. And in all that time, we spent a grand total of one hour, on the last day of class, to cover all herbaceous plants.

Ornamental grasses took up exactly zero minutes. But as they say, that was then ...

Over the ensuing decades grasses took the plant world by storm. Producers and designers started to appreciate the cultural tenacity, textural uniqueness and overall usefulness of these plants and started to scour the globe for attractive and adaptable grasses to use in landscapes and gardens.

First, a few benefits of the better grasses. They are generally fast growing, some making plants more than 10 inches tall and almost as wide in a single growing season. Once established they will keep going and going, year after year. Secondly, they offer a textural package mostly unavailable to gardeners from other plants. Their produce arching and wispy forms that sway in the slightest breeze. They form the perfect foil for bold textured plants. Their seed heads offer garden interest fall and into winter. And finally, they are easy to produce from either seed or division.

But there are drawbacks to some of the grasses that have weeded their way to market. Some have become wildly invasive and others can be a bit weedy. The devil, as they say, is in the details.

There are scores of great ornamental grasses out there but in the interest of space considerations, here are a few grasses to consider — and one to avoid.

Feather Reed Grass (Calamagrostis x acutiflora ‘Karl Foerster’) — The darling of the ornamental grass world for a long time, it was named a 2001 Perennial Plant Association Plant of the Year. This hybrid of two European/Asian species grows to be an almost architectural plant to about 5-feet tall with narrow, erect shape. It holds up well to wind and rain and even holds its shape through much of the winter. It makes an excellent narrow screen planting. Showy seed heads show up in late summer and remain effective through the fall and into winter. And those beautiful seed heads do not make for an invasive plant!

Switch Grass (Panicum virgatum) — This is one of the most popular of the large, North American native grasses growing to 6-feet tall or more. It is one of the most common grasses of the tall grass prairie ecosystem that once covered much of the middle of North America. Switch Grass is prized for its fine texture, broad shape and airy clouds of seed heads late in the season, set off by often reddish leaf tips. It is excellent for use in large masses or as isolated clumps emerging from mixed perennial beds. There are numerous excellent selections including ‘Heavy Metal’ and ‘Cloud 9’ that are both large, robust selections. Smaller forms that top out at more like 3-4 feet tall include ‘Shenandoah’ and ‘Northwind.'

Prairie Dropseed (Sporabolis heterolepis) – This is an excellent small dry-land grass for sunny gardens. Growing to less than 2-feet tall, it offers almost hair-thin foliage in a low arching mound topped with delicate, dancing seed heads above on thin, wiry stems. It gives the designer something to play with for low masses in contrast to bold textured perennials throughout the season. Long lived and dependable.

Blue Grama (Boutelua gracilis) — Another of the shorter grasses, Blue Grama grows to less than 2-feet tall with fine, blue/gray foliage and uniquely shaped, purple tinged flowers in mid to late summer. The cultivar ‘Blonde Ambition’ has chartreuse colored flowers held slightly higher than the species. Both the species and cultivar offer unique and interesting texture through fall and into the winter.

And one to avoid ...

Maiden Hair Grass (Miscanthus sinensis) — Probably the most commonly sold and planted ornamental grass in our area is actually one of those dreaded invasive offenders. The Asian native Maiden Hair Grass and its many cultivars are among the most invasive of the ornamental grasses. They are vigorous, attractive summer and fall and are easy to grow. The problem is that they produce tons of viable seed that floats on the breeze and germinates just about anywhere it lands. Across Kentucky and much of the Southeast it is a major invader of open spaces and once established is extremely difficult to control. It’s one we don’t recommend for obvious reasons.

Yew Dell Botanical Gardens, 6220 Old Lagrange Road, yewdellgardens.org.