Add some class with ornamental grass

Ornamental grasses are a very versatile part of landscapes today. They can be planted alone, in groups or as a part of a perennial or annual garden. The spectacular seed heads are a great attention-getter.

Grasses are very carefree plants that make a beautiful addition to just about any area.

However, most grasses do require some care.

Many of us have questions. When do we cut them and how do we do it? Then what?

I hope my research will help.


An important thing to remember is that there are two classifications of grasses, warm season and cool season.

Warm season grasses do not usually begin growing until late spring or early summer, when the weather begins to warm. Their main growth and flowering occurs during hot weather, and they begin to turn shades of brown as winter begins.

Cool season grasses tend to grow in the spring before temperatures reach about 75 degrees, and then again in the fall when temperatures begin to fall. These grasses usually keep their color all summer but do not grow when it is hot.

There are also what are referred to as evergreen grasses (i.e., sedges and rushes), but they are not specifically (botanically) classified as grasses.

Warm season grasses should be cut back in the fall or early winter when they turn shades of brown. They should be cut to about 3 to 6 inches above the soil level.

Some folks prefer to leave the grasses for interest during the winter. If warm season grasses are not cut until late winter, they should be cut to ground level before new growth begins. Snowfall is a consideration when leaving the grasses through winter. If snow happens to be heavy, it will cause the grasses to fall and they will not come back up. This can make the job of cutting in late winter more difficult.

A few examples of warm season grasses are Prairie Cord Grass (Spartina), Switch Grass (Panicum), Hardy Pampas Grass (Erianthus), and Perennial Fountain Grass (Pennisetum).

Cool season grasses should be cut back in very early spring. If these grasses are cut too short, it will harm the plant. Therefore, cut only about two-thirds of the plant.

Cool season grasses remain semi-green unless they do not receive enough water throughout the season. In this instance, they will turn brown.

Some popular cool season grasses include Fescues, Blue Oat Grass (Helictotrichon), Tufted Hair Grass (Deschampsia) and Autumn Moor Grass (Sesleria).

It is not always easy to cut back large clumps of grasses. The blades can be itchy and / or razor sharp. Therefore, PPE (we’ve heard that often during the COVID-19 epidemic) is a must when preparing to cut. We should never take that lightly.

Our personal protection equipment for the garden includes long sleeves to get around the clump, a thick pair of garden gloves, and eye protection. Tying grass with cord, rope or even bungee cords will make cutting easier and clean up simple.

If you have a small clump, garden shears or a knife will work. On the other hand, if it is a very large clump, you may have to bring out the big guns — a hand-pruning saw or an electric hedge trimmer can make the job much easier.

The tough root system is what makes grasses heat and drought tolerant but, unfortunately, also makes the plants very difficult to divide, and there is no easy way to do it. Division is done in the spring prior to new growth or late summer or early fall following the growing season.

When the grasses begin to suffer from die-out in the center, the job becomes challenging. A very sharp shovel, a knife, axe or possibly a chain saw is necessary to cut through the core. At this point, the clump can be cut into pieces and the dead core disposed.

Dolak is an OSU Mahoning County Extension Master Gardener volunteer.


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