Subject: Thistles

From: Mark Ludwig <[email-masked]>
Date: Thu, 20 Feb 1997 11:47:07 -0600

At 07:55 PM 2/19/97 +0100, you wrote:
>rec'd this comment when asking for germination on the very excellent
>propagation list.  since Im somewhat unfamiliar with the species Im
>wondering what others think about a small planting of milk thistle in a
>zone 4 medicinal snake mound.
>
Hi Mikel,
Been studying "weeds" in school including thistles and have a few thoughts
based on what I know of other species in WI.
The worst of our thistles is probably Canada Thistle (Cirsium arvense) as it
is a perennial spreading by seed and rizomes. If milk thistle spreads like
this it will probaly be a pest in the garden over time.  Our other thistles;
Plumeless (Carduus. acanthoides), Bull (Cirsium vulgare ) and Musk (Carduus
nutans),  are all aggressive biennials, but much easier to control as you
can effectivly break their life cycle by mowing or snapping their taproot at
stratigic points in their life cycle (just befor flowering).  I assume your
going to harvest the seed, so if the root system isn't a spreading type,
it's probably OK to plant; BUT I'm not sure it's advisable due to the chance
that you will miss some seed now and then  and get a wild/naturalized
population heading into your neighbors corn field.
Mark