Category Archives: Noxious Weeds

Crellin Meadow Weed Update

7/23/2010 Note from Ellen: Today I received an email from Renee P. following up on her 2009 weed management project in the Crellin Meadow. This meadow is located in the drainage area just north of Crellin Lake and is contiguous with the restoration area that the Ecology Committee and GVM Office staff have working on doing the last three seasons. Please click this link to read about Renee’s weed strategy. https://gvmecology.wordpress.com/2009/09/01/new-strategy-for-attacking-canada-thistle-in-crellin-meadow/ Thanks Renee!

“Hi Everyone, I was just out in Crellin Meadow and want to share how amazed I am at how good it looks sans thistles. The grasses are chest high. There’s Phalaris, Glyceria, Poas, and possibly Luzula (!) thriving in there with all the usual sedges, willows and orchids.. It’s literally been ‘released”.

Do yourselves a favor and take an outing to see what can be done in the course of one year (1.5 seasons). This is not to toot my horn. I am just amazed and enjoying it thistle free for the first time in the 11 yrs we have been here. I can host you or not – it’s worth seeing if you remember previous years. I’d like to release more wet meadows in GVM.”

Hunting for Musk Thistle at Riddle Lake

Musk Thistle Rosette at Crellin Lake
Musk Thistle Rosette at Crellin Lake

4/27/2010 From Ellen: “I have  adopted Riddle Lake this season and will continue the weed management work that the Ecology Committee started last season. This lake, located about a 1/2 mile inside Gate 1, is one of three in GVM. As for the other two, Batterson  Lake is managed by Judd and Crellin Lake by Jeff and Peggy. It  has  been a very late season in GVM, but I found signs of spring: a few Pasque Flowers at the SW end. Nearby, I located (and dug up) 100 Musk Thistle rosettes and just 1 mullein rosette. I also collected trash (not too much) along the south shore.”

Milestone Herbicide Info

9/1/09 We had two follow-up questions from our blog post “New strategy for attacking Canada thistle in Crellin Meadow” about repeated use of Milestone and about using Milestone in riparian areas.

On 9/2/09 Tim D’Amato replied “In my experience, broadcast spraying Canada thistle once with Milestone does an excellent job. Spot-treating some escapes the following year may be necessary. I think this is evident at the plot sites on Haystack Meadow that Phil Westra and I sprayed a year ago.  Milestone is labeled for use in wetland areas.”

9/3/09 For further details, Dow’s TechLine Publication Winter 2009 said yes: “Milestone can be applied up to the water’s edge on terrestrial sites.” I’ve excerpted parts of this article below with registration info, half life, FAQs. The article also references research on nontarget plants by Peter Rice, Division of Biological Sciences at the University of Montana.

Continue reading Milestone Herbicide Info

Three 2009 Sulfur Cinquefoil Sightings in GVM

1) 8/4/09 Renee Popp identified Sulfur Cinquefoil (Potentilla recta) on Filing 1 Lot 79 and marked it with orange flags for others to observe.

2) 8/7/09 Renee Popp emailed Steve H. (GVM Manager), Judd (Ecology Committee Chair) and Tim D’Amato (Larimer County Land Steward Manager) that she has found a List B noxious weed: “I found another sulfur cinquefoil site again possibly with only one plant. This location is in the USFS/GVM greenbelt complex around Haystack Ct. This would be roughly 1/2 mile west of the first site I found it with Manhead Mtn in between. I pulled it because I wasn’t sure I could use chemicals on the USFS part. Do we have any type of agreement with the USFS for the management of that small parcel? Looks like abuot 20 acres just guessing. I pulled all the musk thistle heads in there and would like to return to spray the remaining musk plants. Am I allowed? Thanks, Renee”

3) 9/1/09 Jim Erdman spotted Sulfur Cinquefoil near Horn Peak Ct after his nature walk. He was with Andre, Karen, Mary, and Wynne.

New strategy for attacking Canada thistle in Crellin Meadow

Renee Popp at Crellin Meadow 8/19/09 Note lack of Canada Thistle flowers
Renee Popp at Crellin Meadow 8/19/09. Note lack of Canada Thistle flowers (click image to enlarge).

I asked GVM resident Renee Popp, what her thoughts were on controlling the noxious weed, Canada thistle (CT). As field botanist of over 30 years, both with the USDA Forest Service and as an independent contractor, Renee is an ardent supporter of noxious weed management as a way of improving habitat for our rich store of native plants. This season Renee had a break in her field schedule that allowed her to implement a plan she has been wanting to try for 10 years. On 9/1/09 she wrote:

“Many times I’ve seen the County and now GVM come spray Crellin Meadow (NW of Crellin Lake) where I live, sometimes twice per year. And every time the CT sprouts right back like nothing happened. I think that’s because the treatment is too little too late.

CT operates from an extensive underground root system. To get CT on the defensive, the roots’ reserves need to be compromised if not wholly exhausted. A 4-wheeler with a boom to apply herbicide works great on flat farmlands. However, in the case of Crellin there are trees and wetlands that prohibit a 4-wheeler from making clean sweeps with complete coverage. These obstacles result in pockets of the infestation left untreated. Any plant that is green and photosynthesizing is sending nourishment to the roots.

This year I checked out a spray canister filled with Milestone provided by the GVM office. I spot-sprayed everything that GVM’s 4-wheeler didn’t get. And when a single sprout came up, I sprayed again and again and again. I’ve been re-spraying every week to snuff out new sprouts. It’s been held down long enough now that I expect to see some difference next year.

I realize that the CT population in Crellin Meadow is most likely here to stay, but I still believe we can slow its spread and reduce its size. For this reason I emphasize finding and spraying plants at the outer boundaries as a first priority on this or any other CT infestation.

In the end I guess the message for CT is that intensity may be more important than extensivity. Strategic, complete, high frequency, and targeted hand-spraying may be the keys to reducing and even eliminating weeds vs. just living with weeds and herbiciding broadly forever.”