Re: RE: Roundup and other herbicides
- Subject: Re: [sibrob] RE: Roundup and other herbicides
- From: B* H* <c*@cablespeed.com>
- Date: Mon, 19 Jul 2004 22:20:03 -0400
Like a lot of other people we use Roundup (2.5 oz/gallon) all year round in
the Siberian beds (though always trying to avoid direct contact of the
spray with the irises). Every year a handful of flowers show the pale
colors and changed form typical of Roundup injury, but I've never seen the
vegetative parts of a plant much affected or had one die, so there is some
degree of resistance which is a blessing. Here are a few more observations
on herbicides and Siberians:
Snapshot (2.5% granular) is a pre-emergent herbicide mixture - a sort of
improved version of Treflan. We use it very widely around the new seedlings
and it has never caused any problem. As long as it is rained or hoed in
soon after application, it does a great job. Poast (common name;
sethoxydim) is a grass-selective compound. I never saw any problems with
Siberians oversprayed with this. However, a few years back I switched to a
closely-related compound Select (clethodim) because it is supposed to
control annual bluegrass which Poast doesn't. This was a mini-disaster.
Sprayed on the plants while they had bloom stalks, it blasted every bud -
they just dried and withered. Fortunately it was used on a very limited
area. The plants themselves weren't killed, but it was a nasty surprise and
the last time I used Select. Not entirely grass-specific, whatever the
claims! The last grass-specific herbicide that we use now as a primary
compound is Fusillade II (fluazifop-P-butyl). This seems to be pretty much
harmless to irises, though I haven't sprayed them when in bloom. Lastly, a
really useful compound is Lontrel (Stinger; common name: clopyralid)) which
is a plant hormone analog like 2,4-D. It works wonders on thistles and
compositae like dandelions and ragweed and a few other significant weeds.
It doesn't seem to harm the irises but it does cause twisting of the flower
stems so it shouldn't be used when they are in bloom. With care, you can
get just about every weed with these compounds. But, these mixed
experiences do clearly show that the flowers are often the most sensitive
part of the plant and that, as Harold says, some initial tests on a limited
area before believing anything you read or are told can save some grief. It
would be interesting to find out how other people with large plantings
handle weeds. Weed pressure is relentless and makes most of the work in
growing Siberians for us. Bob Hollingworth
------------------------ Yahoo! Groups Sponsor --------------------~-->
Make a clean sweep of pop-up ads. Yahoo! Companion Toolbar.
Now with Pop-Up Blocker. Get it for free!
http://us.click.yahoo.com/L5YrjA/eSIIAA/yQLSAA/2gGylB/TM
--------------------------------------------------------------------~->
http://groups.yahoo.com/group/sibrob/
Subscribe: sibrob-subscribe@yahoogroups.com
Post message: sibrob@yahoogroups.com
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/sibrob/
<*> To unsubscribe from this group, send an email to:
sibrob-unsubscribe@yahoogroups.com
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
