2015-11-16_REVISION - M1977393 - Laserfiche WebLink

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October 5, 2015 City of Boulder Open Space Open Space and Mountain Parks Department 7315 Red Deer Dr, Boulder, CO 80301 www.osmp.org Varra Pit Vegetation and Invasive Plant Species Management Recommendations: This document is to provide vegetation management recommendations in order to effectively control invasive plant species for the Varra Pit reclamation area on the Varra, East property (Figure 1). The plan is divided into three distinct areas. 0.9 Acre Area The vegetation community on the western most 0.9 acre area is in excellent condition and provides ample competition against invasive plant species. There is a small, 0.001 acre patch of diffuse knapweed in the northeast corner of the polygon that can be clipped and bagged or spot treated with a suitable herbicide in late September or early October. Exact timing of herbicide depends on growth of rosettes in late summer/early fall, typically coinciding with late growing season precipitation. Periodic, on an as needed basis, clipping and bagging of flower heads or spot herbicide treatments of invasive plant species including, but not limited to diffuse knapweed, musk thistle, or Dalmatian toadflax will be necessary in this area until reclamation is deemed complete. 4.8 Acres Area The western portions of this area have good stands of seeded grass species, however, diffuse knapweed is also common. The eastern half of this section has dense stands of diffuse knapweed with very little desirable, seeded vegetation. Diffuse knapweed management in this area requires broadcast application of a suitable herbicide in late September or early October. Exact timing of herbicide depends on growth of rosettes in late summer/early fall, typically coinciding with late growing season precipitation. The western half should also receive a supplemental seeding to provide additional competition against further establishment of diffuse knapweed. The eastern portion of this area would require complete seeding and seed bed preparation in order to increase the cover of native vegetation which will provide competition and limit future diffuse knapweed growth. In addition, seeded areas should be temporarily excluded from cattle grazing (likely three to five years) to allow time for seeded areas to establish vegetation. Cattle grazing should return after establishment. The northern edge of this area, along the north side of the old road, has a high density of diffuse knapweed and musk thistle. This strip would require summer mowing followed by a broadcast application of a suitable herbicide in late September or early October. Exact timing of herbicide depends on growth of rosettes in late summer/early fall, typically coinciding with late growing season precipitation. Periodic, on an as needed basis (likely annual for three to five years post seeding) this area will require clipping and bagging of flower heads and/or herbicide applications of Open Space...Preserving a Wild Idea!