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