This is a public-interest archive. Personal data is pseudonymized and retained under GDPR Article 89.

Canada Thistle/L. Sullivan

I also have a significant problem with Canada Thistle (Cirsium arvense) in
my 20 acre prairie restoration/reconstruction site in south-central
Michigan.  This dioecious perennial alien (native to Europe, not Canada) is
extremely difficult to control.  Indeed, often I will not plant a site with
forbs until I am certain the seed bank of this species is substantially
depleted.  I wish I had a solution to this problem.  I have examined many
prairie restoration/reconstruction and remmant sites in the midwest and at
certain sites this alien is still a substantial problem even decades after
the onset of restoration/reconstruction.  Nevertheless, I have observed the
following; on heavy clay soil, this alien will "out-compete" virtually all
native forbs including the so-called "clay busters", however, on very rich
("ideal") prairie soil, eventually after many years, the native forbs and
grasses will "out-compete" this alien.  When asking advice on the control
of un-wanted plant species, the knowledge of the type of soil is critical
in the evolution of a meaningful solution.  In heavy clay soil, certain
native grasses, however, will eventually out-compete this alien (e.g., Big
Bluestem, Indian Grass, Switch Grass), such still taking many years.  I
have found that mechanical solutions (e.g., pulling, mowing, etc.,) are not
very effective (although the roots of this species can extend many feet
deep in the soil, the horizontal roots extending from this deep root will
yield, in no time, many plants.  While time consuming, I continue to
spot-spray this alien with an amine derivative of 2, 4-D (in areas of my
site that are without forbs, i.e., only native grasses, I frequently
field-spray this plant with the above herbicide using my tractor-field
sprayer unit.
   I wish that I could be more encouraging and I can certainly identify
with your problem of "emergy and time is waning" and a "sore back".  With a
restoration site as large as 18-acres, one must be as efficient as
possible.  I have had no experience with Wild Parsnip (Pastinaca sativa).
If I can be of further assistance, please do not hesitate to contact via
e-mail and/or via the telephone [(517) 626-6996].
Cliff
(Clifford W. Welsch, a "native grasslander" in south-central Michigan)






---------------------------------------------------------------------
To sign-off this list, send email to majordomo@mallorn.com with the
message text UNSUBSCRIBE PRAIRIE
Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index