Thursday, March 7, 2019

Eastern Bottlebrush Grass

Bottlebrush grass, Elymus hystrix, is a pretty common native species found in open shade and woodland edges in Maryland.  Its native range is from Maine to Georgia and westward to the Great Plains.   It is a cool season grass, meaning that it begins grows actively when soil temperatures are between 50 and 65 F.  Attractive seed heads are produced in June and these often persist into the fall.  Like most cool season grasses it shuts down in the heat of summer, but comes back to life in the fall, sometimes staying green all winter.  I am looking at using this grass to help fill in the woodland edges after removing the invasive Japanese stilt grass, Microstegium vimineum.  Ideally once it gets established it will grow up and shade the ground before the stiltgrass germinates later in the spring.

Eastern Bottlebrush Grass at the end of June growing along a trail near Harper's Ferry, WV

Rather than buying new seed, I harvested some from my existing plants last October and stored them dry in a refrigerator at about 42-45 F.  They were left there until I planted them in mid-February under lights.  Bottlebrush grass seeds do not require moist stratification to get them to germinate, just cold storage for a few months.

Since I have had less than stellar success with starting seeds I thought I would compare different ways of planting the seeds and see how well each germinated.  This was a limited study with only 8 seeds under each of 8 conditions.  All were planted in a soil-less seed starting mix and put on a warming pad to give a soil temperature between 65 and 70 F.  The long awns on the seeds, which give the brush effect, are not easily removed.  I pulled the awns off of each individual seed.  For these I planted one set vertically, and the next horizontally, each about a quarter inch deep.  The third set I planted vertically about a half inch down.  I repeated these conditions using seeds with the awn still attached.   

Here's the first leaf of Eastern Bottlebrush Grass.  The inital shoot has a reddish
 tinge that makes it harder to spot on the dark background. 
The last set of seeds were moved to a colder refrigerator for about a month.  I thought this might simulate winter conditions better.  One set of these I cleaned and planted horizontally, and the other was with the awn attached and planted vertically. 

Seeds began germinating after 9 days.  Rather than going into too many details the results indicated that seeds that were cleaned germinated more quickly, but after a month there was little difference between cleaned and uncleaned seeds.  Where I did see a difference was with colder storage.  Seeds stored in the back of the refrigerator germinated at half the rate of the others stored at about 44 F.  I suspect at the back of the frig, where the coldest air comes in, temperatures would sometimes drop below 32 F.

Now I have about 30 plugs of a native grass that I can grow on to use in my battle against stiltgrass.