Deer Country: Why Deer Don’t Eat Ornamental Grasses

Fountain grass in summer

In my recent posting, “Deer Country: Bib Jeans, New Trimmer, 26 Flat Tops” [Feb. 15], I commented, “Best of all, deer don’t eat fountain grass—and most other ornamental grasses.  I suppose the reason is that the grass is too tough for them to easily bite off and then chew.”

Bettye Ames, a Howard County Master Gardener, emailed me a more enlightened reason why deer don’t eat ornamental grasses:  “The stems and leaves of ornamental grasses contain silica (read ‘glass’), which can cut the mouths of grazers.  This same silica may cut our dear gardening hands and arms if we forget to put on gloves and long sleeves while cutting our ornamental grasses.”

I knew ornamental grasses can be tough.  I knew my old electric trimmer sometimes mangled tough fountain-grass rather than cutting it cleanly.  I knew it was easier to cut stems than to pull them off.  But I didn’t know about the silica.

An Internet search quickly confirmed Bettye’s explanation.  Both Wikipedia and Pediaview contain identical sentences: “The leaf blades of many grasses are hardened with silica phytoliths, which helps discourage grazing animals. In some grasses (such as sword grass), this makes the edges of the grass blades sharp enough to cut human skin.”

Fountain grass in fall

Another website mentioned that some grasses contain sufficient amounts of silica to dull cutting blades.  Several sites used bamboo as an example of a grass containing so much silica that its stems are rigid.

As I read, I involuntary shuddered, and hair on the back of my head stood up.  I remembered visiting Hugo, a school mate, about 65 years ago.  We thought it was fun to explore the remains of the nearby, abandoned slaughter house that had burned several years earlier.  At some point we explored a nearby patch of tall grass and thought we would pull enough to make a hiding place.  I grabbed a handful of grass and pulled, and as it slid between my right palm and index finger, I felt the grass slice through my flesh.

I screamed and, dripping blood, ran to Hugo’s house.  I don’t remember all the details today, but I do remember someone holding my bloody hand under a gushing stream of cold water as someone else pumped vigorously.  Soon the bleeding stopped and my wound was taped shut.  A faint scar by the second joint on the inside of my index finger reminds me of that day.  I suppose the old pump at Hugo’s house has long since disappeared and the site remains undesignated as a national historic site, despite the blood shed there.

Thank you, Bettye, for widening our knowledge about ornamental grasses and why deer usually avoid them and for the reminder to wear gloves when we work with the tough ornamental grasses.