Regional Gardening Reports :: National Gardening Association

In the Garden:
Northern California Coastal & Inland Valleys
September, 2010
Regional Report

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Ornamental grasses on display at the Sunset Gardens in Menlo Park.

Ornamental Grasses

You see them everywhere - in median strips along El Camino Real, along the freeway, in private and public landscapes, even in the wild. Ornamental grasses are being used heavily these days because they will tolerate stress in the form of drought, poor soil and infrequent maintenance. Does that mean that ornamental grasses are right for your own yard?

In the past 20 years ornamental grasses such as purple fountain grass (Pennisetum), fescues, sedges, rushes and yes, even pampas grass (Cortederia) have become common in the landscape. Sometimes an ornamental grass isn't really a traditional grass plant at all. Look-alike plants such as society garlic (Tubalghia), lilyturfs (Liriope) and even daylilies (Hemerocallis) are grouped into the ornamental grass classification because of their strap-like foliage and forgiving nature.

Basically there are cool season grasses and warm season grasses. Dormant foliage of warm season grasses provides essential habitat for over wintering wildlife. Warm season grasses grow best between 80 and 100 degrees F and grow rapidly during spring and summer. They usually go dormant in the winter. Cool season grasses grow during the cool winter months and generally require more moisture than their warm season cousins.

There are differences in growth habit as well. Running grasses do their growing underground by runners and can quickly get out of control. Clumping grasses are more well-mannered and will expand and increase in girth by sprouting from the base of the plant.
There are six primary categories of ornamental grass shapes; tufted (Festuca), mounded (Pennisetum), upright (sedge), upright divergent (flax), upright arching (Miscanthus) and arching (Setaria).

Many ornamental grasses are grown primarily for their flowers such as the many varieties of Pennisetum, natal grass (Rychelytrum) and cotton grass (Eriophorum). I love the striped foliage of zebra rush (Schoenplectus), the smokey softness of purple muhly (Muhlenbergia) and the variegated foliage of ribbon grass (Phalaris).

Some ornamental grasses are grown for culinary purposes. Lemon grass (Cymbopogon citratus) carries the fragrant aroma of citrus and the tender growth at the base of the stalks is used in many cultures for cooking and medicine. It grows well in our climate and is a handsome plant, tidy and noninvasive. It does well in containers but does need protection from frost if it is to be grown as a perennial.

Sedges and rushes are best grown in boggy or wet soils. Papyrus (Cyperus) is an example of a sedge. Flowers are borne on umbrella-like heads and add interest and texture to a pond or pool area.

Maintenance of ornamental grass is basic. The plants should be cut back to the ground at least once a year to remove faded foliage. Grasses should be cut back prior to their growth burst. Warm season grasses, which put out new growth in the spring, should be cut back in late winter. Cool season grasses should be cut back in the fall.
Watering is best done at ground level. Overhead water may cause the flowers to droop or worse, develop fungus disease. Drip irrigation or hand watering is best. Some plants such as Cortaderia will survive with no supplemental water at all. Mulching will preserve moisture and prevent weeds from growing until your new grasses have become established.

It's important to select an ornamental grass that suits your landscape. If your yard is small, don't select a plant that will grow to 6 feet. As always, select sun loving plants for sunny areas and low light plants for shade. The list of ornamental grasses includes something for everybody!

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Today's site banner is by nmumpton and is called "Gymnocalycium andreae"