Now that fall has arrived, we’re all enjoying peak plume season for many of our favorite ornamental grasses. Unfortunately, there are a few significant mix-ups in the trade. The top photo is our native Eragrostis spectabilis, known as purple love grass. I’ve long admired this beautiful, but short-lived native, but have declined to offer it because of its propensity to seed around much too vigorously in the garden. In prairie restorations or less-tended gardens, it can be a spectacular addition. Hardiness is Zone 5-9.
Because most nurserymen aren’t plant taxonomists, you can perform a Google images search and find several on-line vendors who pretend to offer Eragrostis spectabilis, but show photos of the grass below, known as Muhlenbergia capillaris. Who knows which of the two they are actually selling.
If that’s not confusing enough, the plant below is known in the trade as Muhlenbergia capillaris or Gulf Coast muhly grass/pink muhly grass. The only problem is that this is actually a different muhlenbergia species. All of us have taken this name for granted, but as our Director or Horticulture/Gardens, Patrick McMillan taught us, all commercial plants labeled as such are actually Muhlenbergia sericea. We are updating our records and this name change will be implemented in the near future.
The misidentification originated with a Florida taxonomist, who mistakenly lumped three muhlenbergias together…a problem that can occur when you only study dead/smashed plants in a plant herbarium. As it turns out, the two plants, Muhlenbergia capillaris and Muhlenbergia sericea (also formerly known as Muhlenbergia filipes) are nothing alike.
The true Muhlenbergia capillaris is a rather homely plant that few folks would want in their garden. Muhlenbergia sericea, on the other hand, is a stunning ornamental plant, commonly known as sweet grass, and used for making those amazing hand-woven baskets that you find for sale in towns like Charleston, SC.
Such nomenclatural faux pas take decades, at least, for nurseries to get the names corrected since the public knows and purchases plants under the wrong name. This problem is far too common. The shrub, Ternstroemeria gymnanthera, was originally mistakenly identified as Cleyera japonica, and that mistake still persists over five decades later. Most gardeners despise name changes, often not realizing that many instances like these aren’t changes, but instead corrections of an earlier identification mistake.
You can learn more details about the mix up by reading Patrick’s article about pink muhly grass.