Houlton Farm Planning Committee Meeting 2016-02-02

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care. Remnants with high diversity should be spot treated, not broadcast -treated. It is recommended to treat first with the least impactful chemical, monitor to see if that works, and then try another if it does not work. Degraded and highly disturbed areas can be treated a little less gently, perhaps using broadcast applications. Always follow the product label when using any chemical for weed control. Treatment should be done before the target plants form seed, so late spring and early summer are best. Professional pesticide applicators are required for herbicide treatment. Canada thistle While native thistles are not generally problematic, exotics such as C a iistle are clone -forming perennials that can greatly reduce species diversi fields and restoration areas (Hoffman and Kearns 1997). A combination a and mechanical control methods may be needed. Chemical control is most eff a wh plants are in the rosette stage and least effective when the plants are .n . Where asses and sedges are present, use of a broadleaf herbicide su as 2,4-D is recomm , since 2,4-D only affects dicots. 2,4-D is most effective wh pplied -14 days bef e the flowering stems bolt. It is applied at a rate of 2-41 si ckpack or tractor - mounted sprayer or in granular form. Dicamba could used, with the advantages that it can be applied earlier in the spring at a rate of 11b Another chemical that has been used for thistles is aminopyralid(" a"), which plied at bud stage. Aminopyralid will affect other species an r residu ctivity than some other chemicals, so use with caution—typically u it on es/clones of thistles and avoid areas of higher diversity. Plants that esp ❑ treatment or that are more widely dispersed could be contri&d mecha ly. Mechanical control, invo g sevely cuttings pWe ar for three or four years, can reduce an infestation if timed tly. T cut is when the plants are just beginning to bud because their food ar lowest. If plants are cut after flowers have opened, the cut plants shoul moved because the seed may be viable. Plants should be cut at lZth .rough eason. Late spring burns can also discourage this speciespri ns can courage it. Burning may be more effective in an establi, whe mpetr 'on from other species is strong, rather than in an old field, wetition i ely to be weaker. Sweet clover White and yellow set clover are very aggressive biennial species that increase with fire. Where sweet clover is found, it should be controlled in conjunction with treatment that attempts to eliminate smooth brome, if prairie restoration occurs. Sweet clovers are common plants in agricultural areas, so if restoration is implemented, the project area should be surveyed for this species on an annual basis. Often times, following initial brush removal and/or burning, a flush of weedy annuals and biennials such as sweet clover can occur. Well-timed mows and burnings are usually adequate to control these species. Mowing the site, as is typically prescribed for prairie restoration maintenance, should occur when all plants on the site (including sweet clovers) are approximately 12 inches in Friends of the Mississippi W. H. Houlton Conservation Area NRMP .O