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priate for fall application (e.g., picloram, metsulfuron + 2,4-D, or clopyralid + 2,4-D for Russian <br />knapweed as described in Table 1; picloram and dicamba for Canada thistle as described in <br />Table 2) may be effective for mid-winter use. Otherwise, the herbicide should be chosen based <br />on the projected timing of application as described in Tables 1 and 2. Again, the patches should <br />be monitored because re-growth of the weeds is highly likely and repeated applications of the <br />herbicide(s) may be necessary. If the herbicides are not effective with the first application, vary- <br />ing the type of herbicide with different seasons may also increase effectiveness. <br />Following the set-up treatment of chemical control, we recommend instituting a second control <br />phase dominated by cultural measures, i.e., planting competitive desirable species. This can be <br />incorporated as part of the general site reclamation plan. Native to the area are the shrubs <br />broom snakeweed, rabbitbrush, winterfat, and saltbush, and the grass blue grama. If these <br />species are used, care needs to be taken with the use of herbicides, since some of the herbi- <br />cides may also kill the desirable plants. <br />Many of the herbicides target broad-leaf plants and therefore, if continued herbicide applications <br />seem necessary, grasses may be more desirable in the weed patch areas. We recommend <br />grasses historically native to the region's prairies such as buffalograss (Buchloe dactyloides), <br />Indian ricegrass (Achnatherum hymenoides), big bluestem (Andropogon gerardii), little bluestem <br />(Schizachyrium scoparium), sideoats grama (Bouteloua curtipendula), and Indian grass (Sorg- <br />hastrum nutans). Western wheatgrass (Pascopyrum smithii) would also be a good option to co- <br />lonize this area. This assemblage of species would compete well with undesirable species in <br />the area since it is represented by both cool- and warm-season grasses, which would maximize <br />the active growing season of desirable competitors. <br />Although mowing and/or tilling of these small patches may not be effective alone, used in com- <br />bination with herbicide treatment and planting of desirable species this method may improve <br />weed control. As noted in the individual sections (see Sections 3.1 and 4.1), the timing of mow- <br />ing is important, especially with concern that mowing does not harm the competitive desirable <br />species. <br />Following this general two-phase plan, the site should be monitored following treatment to eva- <br />luate treatment success and for the administration of additional measures if they are necessary. <br />Monitoring should be carried out at least twice during a growing season for a minimum of two <br />13 <br />