Appendix L
Maintenance Level Guidelines
Glyphosate is quite effective. Glyphosate should be applied before the plant bolts. Glyphosate can also be applied after bolting, but again there is a risk of the seeds still maturing. Glyphosate can also be applied during the dormant season. The results of dormant season treatment are mixed, some individuals have reported success and others failures. The condition of the rosettes and daytime temperature are probably important factors. Rosettes in good condition on warm days are probably photosynthesizing and Glyphosate would be effective. Stressed plants and plants on very cold days may not be photosynthesizing and Glyphosate may not be effective under these conditions. More research is needed on the use of Glyphosate during the dormant season. These herbicides can be used as a spot treatment method with a backpack sprayer. A 1.5 - 2% solution of Glyphosate is effective. A 2% solution of Triclopyr has proven successful. Triclopyr needs the addition of an agricultural non-ionic surfactant. Herbicide coverage should be thorough to wet all the leaves and stems. Use of high volume equipment (booms, etc) may be possible in highly disturbed areas where there is little likelihood of damaging wanted vegetation. By law, herbicides may only be applied according to label directions. Prescribed burns may make detection of teasel rosettes easier. Small rosettes can be hidden in the litter, while dried grass and forb stems can make complete spray coverage with a herbicide difficult. Either fall or spring burns would open up the area for detection. Fall burns would allow detection of rosettes during the dormant season. There is some evidence that singed rosettes may not be as active during the dormant season, and not as susceptible to herbicides. Fires will not carry well through dense stands of rosettes, so singed rosettes may only be a problem around the periphery of an infestation, or with isolated plants. Additional suggestion on control of teasel Several years of treatment may be necessary to totally eradicate teasel from a natural community. It is important to prevent all seed production so that there is no addition to the seed bank in the soil. It may take several years (even up to 5 or 6 years) of repeated treatment before the seed bank is depleted. It is useful to map locations of infestations and treatment so that they can be readily located in future years. If treated in the early stages of infestation it is possible to cheaply and quickly control teasel. If teasel is noticed outside, but near a natural community, get control of the teasel before it gets into the natural community. As with all exotics, start control before they become a serious problem. Failed or Ineffective Practices Mowing is ineffective because the root crown will resprout and flower after being cut. Even repeated mowing is ineffective. Repeated mowing will stop some plants from flowering, but others will produce short flowering stems that may be short enough to be below the height of the mower. Plants that have been knocked over by a mower and not cut off will lie horizontally and produce short flowering stalks below the height of the mower. Cutting off the flower stalks at flowering time and leaving the flowering heads has been shown to be ineffective. Viable seeds can still develop from the cut stems. The flowering heads should be
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466 Naperville Park District | 2023 MASTER PLAN
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