Open Space Advisory Board Agenda and Packet 2021 02 10

Home Browse Search

Noxious weeds are non-native and invasive plants that disrupt our ecosystems and wildlife habitat. The Colorado Noxious Weed Act requires that county and municipal governments implement management programs to control and prevent the spread of noxious weeds on public lands. The City of Louisville Open Space Division utilizes an Integrated Weed Management approach to control noxious weeds on Open Space properties. These methods include: • Chemical control (use of herbicides): Area 1 • Mechanical control (hand -pulling, digging, mowing, clipping seed heads): Area 2 • Cultural control (re -seeding to establish desirable species): Area 3 • Biological control (grazing) Area 3-Re-seeded Area: This area of Davidson Mesa housed a large prairie dog colony until 2013, when plague infected the colony. As the area recovers from overgrazing by prairie dogs, the Open Space Division has been battling manyweed in- festations in this area. Numerous hours have been spent on weed control, including mowing and herbicide applica- tions. In addition, 16 acres were reseeded to restore the land to native grasses. The area is recovering and many desirable species are returning, but there is more work to do. Prescribed fires will be used to reduce weed cover and promote vegetation restoration. Photo of area heavily infested with common mullein and cheat grass before and after mowing. Area 2-Mechanical Weed Control: Approximately 14 acres of land has been mowed in this area to control noxious and invasive weeds. When timed right, mowing can prevent plants from producing seed, eliminate annual weeds, and reduce seed dispersal. Mowing can also improve the appearance of heavily weeded areas and prevent tumble weeds from moving to new areas. Some of the weeds designated for control in this area include Russian thistle, common mullein, cheat grass, Dalmatian toadflax, and diffuse knapweed. ;y Rows of native grass after drill -seeding efforts in 2014. Native Seed Mix: In 2017, this area was drill - seeded with the following mix of native grasses: Big Bluestem (Andropogongerordii) - 5% Sideoats Grama (Bouteloua curtipendula var. Butte) - 10% Buffalo Grass (Bouteloua doctyloides) - 20% Blue Grama (Boutelouogrocilis var. Alma) - 20% Thickspike Wheatgrass (Elymus lonceolotus var Critona) - 10% Green Needlegrass (Nossello viridulo var. Cuchoros) - 10% Western Wheatgrass (Poscopyrum smithii) - 15% Davidson Mesa Q Trailhead Before -and -after photos of treatment plot showing reduction in cheat grass and common mullein after treatment. Area 1-CSU Weed Control Research Plots: The Open Space Division has partnered with Colorado State University to test the effectiveness of different herbicide combinations for long-term management of noxious weeds and the reestablishment of desirable native species. This area (between the t-posts) contains 13 test plots featuring a variety of herbicide treatments. The main herbicide tested in these plots is Esplanade, which prevents the germination of annual grasses including cheat grass. The intent is to reduce competition for native perennial plants, which have deeper root systems than annual grasses and can tolerate the herbicide. Vegetative surveys were conducted a effectiveness and as- sess the presence of desirable species over noxious weed species. Three years post -treatment, Esplanade -treated areas continue to show a reduction in cheat grass and common mullein as well as an increase in native perennial grass biomass. Look at the plant list on the back of this brochure and see if you can identify any native grasses! 21