Muhly grass, a Pa. native, is a sign of fall

I saw herds of Muhly grass waving in the Pittsburgh breezes this past weekend. That signature wave is one of the signs fall is on its way.

According to William Cullina in his book Native Ferns, Moss and Grasses, his favorite M. capillaris (Hair Awn Muhly) “can take your breath away.” I haven’t quite reached the “hand-me-the-oxygen” level yet, but I know what he’s talking about.

Muhlenbergia capillaris or Hair Awn Muhly is a mounding Pennsylvania native perennial warm-season grass that grows about 3 feet tall and wide.

For gardeners who are going native, Pennsylvania Muhly will be hard to find. The USDA defines the Pennsylvania Muhly as “extirpated.” It’s no longer endangered — it’s been rooted out. It’s gone! Plantsmen have developed many excellent hybrids and varieties to cover our loss and we can only speculate as to whether the newcomers are as beautiful as the native.

Most varieties of Muhly grow well in Zones 5-9, in well drained soil with full sun, although they will tolerate some shade. Muhly thrives in drought or average moisture as long as the soil is well-drained. It will die in standing water. M.capillaris likes soil with a pH of 5.5 to 6.8. It can be used in mass plantings, rock gardens or as a groundcover.

Muhly is deer, disease and drought resistant, will tolerate some shade and requires only an annual haircut. It is definitely an asset in a low-water or xeriscape garden. The plants grow in clumps, (sometimes referred to as herds). During the summer, the leaves stay green, but they morph into a new penny color in the fall.

I think Hair Awn Muhly is particularly effective when used in a drift, although I’ve seen it planted in beautifully composed containers. Its height and growth rate makes the ideal “thriller.” The Muhly’s gray-green thin leaves grow at a slow pace, reaching 18-36 inches long. With good care, it can live 10 years or more.

Like other ornamental grasses, it should be cut back in early spring. Some gardeners think about trimming it around Valentine’s Day. If the new green shoots are starting to push out of the ground, they cut those back too. Muhly should be fertilized three times a year with an all-purpose fertilizer, once after pruning in February, again in June, and a third time in September.

Muhly grass has an understory of leaves and a canopy of flowers that rises 10-12 inches above its base. They float above the leaves in an airy, delicate pattern. The flowers will continue well into fall. Muhly in flower is amazingly rich in color, texture and grace.

It is demure during the summer and easily overlooked, but in the fall it does a belly dance everywhere it grows. The fine thread-like leaves will sway or dance given the slightest breeze. As the seeds ripen they develop into a haze of whites, lavender, rose-purples and rose reds. It’s mesmerizing — and breathtaking!

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