Ornamental Bunch Grasses - May 13, 2009
Jeff Schalau, Associate Agent, Agriculture & Natural Resources
University of Arizona Cooperative Extension, Yavapai County
Ornamental bunch grasses can add interest and movement to any landscape. They come in a wide range of sizes and colors. Most ornamental grasses add year round beauty and seasonal interest with their foliage and blooms. The seed heads remain on the plant lending a graceful accent to what may be an otherwise barren plot. Grasses look their best in mass plantings where they help cultivated landscapes blend into nearby wildlands.
Ornamental grasses also enhance wildlife habitat by providing cover and seeds provide winter food for birds. Another plus is that they require very little maintenance. Once established, they rarely need to be watered, never need fertilizing, and are usually disease and pest resistant. The grass species listed below are well-behaved bunchgrasses widely available in the nursery trade. They are excellent alternatives to pampas grass and fountain grass. I will also offer well as some seasonal maintenance tips.
Deergrass (Muhlenbergia rigens) is native to much of north central Arizona. It grows naturally on banks of seasonal creeks and perennial streams. Use it in dry stream bed plantings or along driveways and as an accent for larger dry area plantings. These plants get large and grow fast. They normally will grow to mature size in a season or two. Give them sun and enough water to equal 15 inches/year after the first month or so of regular water.
Gulf Coast muhly ‘Regal Mist TM’ (Muhlenbergia capillaris) is a small clump grass with narrow, glossy green leaves is native to east Texas. A frothy haze of deep pink flowers covers the plant in the fall. Plant in full sun, reflected heat, or partial shade. It needs moderate irrigation in the summer to maintain a lush appearance.
Lindheimer's muhly (Muhlenbergia lindheimeri) ‘Autumn Glow TM’ is a selection taken from native stands in Texas. This clump grass has a strong vertical form, with slender, light green leaves. Tall spikes of light yellow flowers emerge in the fall and quickly fade to tan. Plant in full sun, reflected heat, or part shade. Moderate summer irrigation will keep the foliage lush in the heat.
Mexican feather grass (Nassella tenuissima) is a fast-growing little grass native to New Mexico, Texas, Mexico and Argentina, at elevations from 5000 to 7000 feet. Mexican feather grass forms a clump of chartreuse threadlike leaves and stems which turns gold in the winter. It is fairly short-lived, but naturalizes in the landscape. Plant in full sun to part shade and provide excellent drainage.
Little Bluestem (Schizachyrium scoparium) is one of the best known prairie grasses growing throughout the tall grass prairie region. Little Bluestem is a drought tolerant clump forming grass widely used in landscapes where it becomes reddish-brown in autumn providing shape, texture, and color into the winter months.
Yearly maintenance for ornamental grasses consists of pruning them during dormancy to allow light to penetrate down into the crown. This mimics grazing and disturbance that would otherwise occur in natural grasslands. I prefer not to create a clean, sheared look but rather a more ragged, natural appearance. On the stouter grasses such as the Muhlenbergia, I would also suggest some controlled “stomping and tromping” which helps remove more of the dead biomass and increases light penetration. I personally prefer to leave the trimmings and spent seed heads on the ground where they can act as mulch.
Timing of grass pruning depends on whether it is a cool or warm season species. Of the grasses listed above, Mexican feather grass is the only cool season species. Warm season species can be pruned in the spring before summer growth begins. Cool season species can be pruned in late summer or fall before cool season growth begins. These bunch grasses can also be divided. This is best done during their season of growth, but before they begin to produce seed heads. Dig out the entire plant, chop it in halves or quarters with a spade or large serrated knife, then replant and irrigate for a couple of weeks to reestablish the root system.
The University of Arizona Cooperative Extension has publications and information on gardening and pest control. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 ext. 14 or E-mail us at firstname.lastname@example.org and be sure to include your address and phone number. Find past Backyard Gardener columns or submit column ideas at the Backyard Gardener web site: http://cals.arizona.edu/yavapai/anr/hort/byg/.
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Last Updated: May 7, 2009
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