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