Wednesday, March 12, 2014

Leavenworthia Barrens Check

After visiting the barrens most likely to contain Draba species, I headed for the southern slopes of a neighboring ridge line to assess the progress of Leavenworthia uniflora.  The barrens with the densest stands of Leavenworthia form a chain along the upper slope of a long east-west running ridge.

A surface covered with limestone pebbles dominates here. 

Beneath the pebbles is a soil layer deep enough for the plant roots to get a good hold.  I found the Leavenworthia to be rather abundant, but of such a small size that they were extremely difficult to see.

The largest plants are only displaying three or four leaves.  Growing conditions over the next month will determine the flowering success of this plant.

Leavenworthia grows poorly in shaded conditions.  Over a period of about ten years I gradually thinned away the cedars to provide more light for the Leavenworthia.  The Leavenworthia have responded favorably to my clearing efforts.

I’m hesitant to clear any more because of the condition of these pre-existing openings.  The soil is good enough to support several species of prairie type grasses and clearings that provide near continuous sunlight through the summer become carpeted with grass.

The grass makes a thick enough cover to effectively block all sunlight from reaching the surface.  Leavenworthia does not grow in the grassy areas.  I don’t want to make the mistake of clearing so much that conditions worsen for Leavenworthia survival.  I’m happy with the way things are now.

Even a little bit of grassy shade causes elongation of the leaf stems and general weak growth of the plant.  Plants in this condition rarely produce more than a single flower.

Several other barrens species are showing healthy growth on this site.  Here is a Western Sunflower, Helianthus occidentalis, emerging from a partially exposed stolon.  These perennial sunflowers begin their growth in late winter.

Western Sunflower growth is more typically at ground level like this specimen.  Most of the growth remains as a basal cluster, but a tall flowering stalk will emerge in mid summer.

Hedyotis canadensis, Canada Bluets, is common in all of the pebbly barrens.  The previous year flower stalk can be seen standing in the center of this year’s growth.

Many aster leaves manage to survive winter on the barrens.  Several species of asters with intergrading characteristics grow in the Leavenworthia barrens.  I usually tackle their identification on days when I crave a frustrating activity.


  1. Hi Steve... That is some rough growing conditions, but these guys seem to be pushing along!!
    Is that snow in the background in one of those photos???
    I imagine the area will be green real soon for you!!


  2. Hi Grace. Your eyes must be doing fine if you saw that snow. Despite a day with temperatures above 70, the deeper snow drifts refused to disappear. Right now the temperature is in the 20's and the wind is whipping the snow showers into mini-blizzards. I guess this storm is going to give you Maine residents a bit more than snow showers.