Why is the Muhly Grass Pink?

16 Oct

Muhlenbergia capillaris


Driving home from working with John on our wildflower atlas project, I noticed something easy to notice…delicate drifts of pink waving in the breezes.  Who says South Florida has no fall color?  The poison ivy turns red, and we have Muhly Grass, mostly planted.  We’ve all seen it, sometimes covering entire moist meadows with fine feathery pinky-purply flower stalks quivering in the breeze.

Today’s pictures all by John Bradford.

No point here in going on about it as a garden species…try Google to be fertilized with horticultural redundancy.  I like, instead, to delve into why the botanical pulchritude.   Not that I know.   But being an ex-teacher, I do know how to write a multiple choice question.

Muhly Grass is pretty in pink, because:

  1. The pink attracts pollinators to the needy flowers.
  2. The pink is sunscreen protecting the delicate flowers.
  3. The pink is advertising:—hey, I taste good, come eat me and spread my seeds.
  4. The pink is a warning:—hey, I taste terrible,  go eat somebody else’s flowers.
  1. Attract pollinators.  Naw, grasses are almost never pollinated by insects.  They go for wind. The Muhly is at peak pink now, but not many flowers are open.  The flowers offer no reward. And I’ve sat and watched for insects,  only to be skunked.
  2. Sunscreen for delicate blossoms.  A more-compelling idea, but not convincing.   The pink coloration extends strongly into non-flowering parts probably not that sensitive to sun.   Also, a few other grasses have pink up top but, again, it is not distributed to offer PF50.  Moreover, why would sunscreen be vivid eye-grabbing pink?   Seems to be a flag, so read on.
  3. Grasses get around in part inside the animals that graze on them,  although wind is clearly more important by far.  No data on internal grass seed transport handy (it is after 1 AM), but the idea that the pink color serves this purpose is contradicted by one of Muhly’s commercial selling points, that deer hate it.   Wondering why, I did something characteristically stupid.  Shhhh. Don’t tell my wife.  I popped some in my mouth and chewed my cud.   BAD IDEA!   It tastes awful, but the real punishment was a “physiological reaction” in my mouth lining for over an hour, maybe even a wee bit now.  (Or is that the wine I’m drinking as I type?)   What it would do upon being swallowed is worrisome.   Nasty. 
  4. The unpalatability points to choice 4, deterrent.    What is the worst thing in the world for a grass, except maybe a lawnmower or brush fire?   Having its precious flowers grazed off.   Who knows what herbivores Muhly Grass evolved with, no doubt buffalo, mastodons, and other hungry beasts now extinct.  In 2021 deer will have to represent the Herbivore Guild.  So then,  I suspect with no proof the pink tops are “warning coloration.”   How many clear examples of that are apparent in the plant world?

Posted by on October 16, 2021 in Uncategorized


4 responses to “Why is the Muhly Grass Pink?

  1. theshrubqueen

    October 16, 2021 at 3:46 pm

    Muhly with a wine chaser? I ended up at the eye doctor one day after being stabbed in the eye by a Muhly..she kept saying “a what”. What amazes me about Muhly is its range. Maybe the pink helps.

    • George Rogers

      October 16, 2021 at 6:47 pm

      Glad you got over the pink eye. Quite a range for sure, well you know, grasses blow around.

      • theshrubqueen

        October 16, 2021 at 7:36 pm you know another grass that grows here and there?why?

  2. George Rogers

    October 17, 2021 at 9:40 am

    Redtop Natal grass has a red top too…and it grows from here to San Diego.


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