I believe I have reached the maintenance stage in my efforts
to control invasive shrubs at Blue Jay Barrens.
After eliminating all of the large, fruit producing specimens, I spent a
couple of years dealing with masses of root sprouts surrounding the dead stumps. Now I deal primarily with newly arrived two
to three year specimens. The Autumn
Olive in the photo above shows what I typically find during my searches for
invasive shrubby species.
Birds are the primary transport mechanism bringing seeds of
invasive plant species onto the property.
Seeds passed through the gut of a bird arrive via bird droppings. The bird’s digestive process softens the hard
seed coat, making it a high likelihood that the seeds will germinate come the
next growing season. Seedlings arising
from this type of process are usually found growing in a closely packed clump
only a few inches across.
A typical clump consists of 8 – 12 individual plants,
identifiable here by the light colored stumps that remained after the tops were
removed. The seeds are most often
deposited in the fall. By the time the
seeds germinate in the spring, they have been separated slightly through the
action of the soil fauna feeding on the non-living portion of the bird dropping,
along with climatic factors such as rain, wind and frost-heave.
I sometimes find first year seedlings, but they are hard to
see because their height rarely exceeds a few inches. It’s more usual to discover the two or three
year old clumps. A plant that reaches
only six inches one year can easily grow to three feet by the following
year.
The seedlings within a clump are in fierce competition with
each other. Only those that make the
most efficient use of the resources within their root zones will survive. Within each clump are one or two stronger stems
that overtop the others. Stems on the outskirts
of the pack frequently grow horizontally along the ground and form roots away
from the group. Here they can develop
with less competition and increase their chances of survival.
The seeds in this group failed to disperse much beyond the
limits of their original deposition.
Horizontal growth was the only way for many of the plants to access
sunlight.
I don’t know how many thousands of seeds are brought into
Blue Jay Barrens by birds each year. It’s
usually not difficult to find fresh seeds on the ground in areas frequently
used by birds for feeding, roosting or loafing.
A good example is this pan of fresh water that I keep near my bird
feeding station.
On the deck beside the pan is an assortment of seeds left
behind by birds coming in to drink or bathe.
From late summer through mid-winter, new seeds are added daily to the
collection. When I empty the old water, done
once or twice each day, there are always a few seeds in the pan. Not all of these seeds come from invasive
species. The majority are Eastern Red
Cedar, a native that happens to be a threat to open grassland and prairie. There are enough invasive seeds though, to
make alien shrub seedlings a permanent fixture here. Fortunately, there are no more invasive
shrubs at Blue Jay Barrens that are mature enough to produce fruit. I am no longer contributing to the problem, I
am just dealing with it.
