Saturday, August 2, 2014

Stipa ichu -- the other hair grass

I've been a fan of Mexican hair grass, or Stipa tenuissima, long before I knew I wanted to be a horticulturalist.  When we teach landscape plant identification at the University of Tennessee, this Stipa always garners interest. While working in the garden, visitors would frequently stop to ask for more information about this hair grass.  And who can blame us?  This lovely grass forms large clumps that resemble long, fine, shining blonde hair.  It's a beautiful plant that is really popular in Tennessee landscaping.

My new favorite Stipa
However, in Kew's grass garden, Mexican hair grass doesn't stand out from the rest.  It sort of blends into the mass of lovely clumps of grasses.  However, one of its cousins shines out from the mounds of Miscanthus and drew my interest from day one -- Stipa ichu (2006-491, ), the Peruvian feather grass.  What's the difference?  Where S. tenuissima resembles a short mass of shining blonde hair, S. ichu looks like a much taller swathe of shimmering silver hair.  Let me put it this way -- the makers of the Harry Potter movies could have used an infloresence of S. ichu to represent unicorn hair in their magic wands, and nobody would have questioned it.

It looks like unicorn hair

Compare the open panicles (left) to
the more silvery, young flower (right)
At Kew, the silvery panicles burst from the fine, green base towards the end of June.  They really shimmer in the morning sun.  These infloresences begin to open and fluff out through July, losing a bit of the silver and becoming more white and a little less reflective.  The open panicles are much lighter, and they get caught up in the wind much more easily.  It's really something to see this plant on a breezy day.  The clumps look like they're dancing with each other.

The silky flowers can also be tawny, white, or purple, and they can grow over a foot tall.  These flowers are held on a plant that could ultimately get 4 feet tall.  The base of the plant is a clump of fine, sturdy, green foliage (Hitchcock, 398).

Native to the Americas

As with its cousin, S. ichu covers a large range over North and South America.  You may find this silvery hair grass in the hills of Mexico, in the plains of Argentina, and even growing up in the heights of the Andes mountains.  In Hitchcock's monograph of the grasses of South America, he noted that S. ichu was fairly common in the upper altitudes of the Andes.  In the introduction, he described the area:

"Most of the region is mountainous, the Andes transversing it from north to south.  Although lying under the Equator, much of the region is so high an elevation that many ranges and peaks are capped with perpetual snow." (Hitchcock, 6)

S. ichu was first botanically described in 1798 from Peru as Javara ichu.  Traditionally Peruvians used "ichu grass" for thatching their homes and other structures (Hitchcock, 398).  The fact that this plant will thrive in the warm, dry, arid plains of Mexico up to snowy peaks m Peru means that it is tough and adaptable.  There is no indication that this plant is in danger of extinction in its natural habitat today, either from the CITES database or the IUCN Red List of threatened species.

Landscape value

This attractive and adaptable
ornamental grass deserves
a spot in any landscape
This is definitely an interesting, eye catching plant that deserves a spot in your garden.  When a group of plant sciences and landscape architecture students from the University of Tennessee came to visit Kew last week, two separately and independently mentioned this plant to me in conversation.  One student said that he couldn't capture the beauty of the grass garden in a photo, so he took some video as well.  I encountered the same problem when trying to get a good photo of S. ichu, so there is a video at the bottom of this post as well.

If you're growing at home, you'll want to give this plant a bit of space.  When planted in an area that is exposed to wind, it kind of whips around and could knock into its neighbors (see video).  Although this silvery grass would make an interesting focal point, it would really shine out en masse.  Consider planting Ajuga 'Black Scallops' as a neighboring ground cover to serve as as a dark foil to this shimmering Stipa.

If you have any questions, comments or suggestions, please feel welcome to leave a comment or send me an email.

To see more photos from this week, be sure to check out the album "They should call it 'unicorn hair grass'" on the Plante on Plants Facebook page.  "Likes", shares and comments are appreciated.

This eye catching grass really stands out from the crowd

All photos and videos were taken by Amanda Plante at the Royal Botanic Gardens, Kew unless otherwise stated in the caption.


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