This is how we should be controlling weeds in public areas in my opinion. A “weed” is commonly defined as a plant growing in a place where it is not wanted. On school grounds, there is usually consensus on the weedy nature of certain plant species such as thistles, crabgrass, and puncturevine that spring up where they are not wanted. Puncturevine can be serious because of the goatheads. There are certainly others.
Weeds need to be monitored periodically. The purpose of monitoring is to determine if, when, where, and why weeds are growing or posing a problem, and to assign priorities for least toxic weed methods of control. The first step in monitoring is to map areas where weeds are growing. This need not be a detailed, time consuming process—a rough map will do. It is important to accurately identify the most common weed species on public property in order to determine appropriate management methods. It is important to record the time of year a particular weed species appears, its abundance, and its impact on the landscape. This information will determine which weeds can be tolerated in a given area and which ones need to be removed and whether new species of weeds are showing up. Without this knowledge, it is impossible to determine the effectiveness of managing methods.
City or county budgets rarely stretch far enough to suppress all weeds, even if that were desirable. Aesthetic standards should be adjusted to take this into account. Assigning tolerance levels helps prioritize budget allocations, facilitate long-term plans, and provide justification for weed management action or lack of action. Identify areas where weeds pose potential health or safety hazards or threaten damage to facilities, and distinguish these locations from those where weeds are considered aesthetic problems alone. For example, puncturevine can cause itching and even pain in some cases, and weeds growing in playing fields or running tracks can pose tripping hazards. Assign low tolerance levels to weeds in such areas, and place high priority on their management. On the other hand, assign higher tolerance levels to weeds growing in areas where nobody goes or along fence lines and consider them low priority for management. Weed tolerance levels are subjective and it would be a good idea to invite a group, such as the city or county officials, maintenance supervisor and a group of citizens that live in the area to tour the area and decide what weed levels are acceptable and where they are not acceptable at all. Of course these tolerance levels can be re-evaluated annually if necessary.
One method of controlling a lot of weeds in an area is with soil solarization. This amounts to a covering of clear plastic to raise soil temperatures high enough to kill the weeds and their seeds. This is most effective when the temperature is 85 degrees and above. Solarization can kill annual and perennial weeds as well as any pathogens in the soil. The plastic should stay in place for 3 to 4 weeks. This can only be used in areas where nobody will mess with it.
When non-chemical weed management methods are not sufficient to solve weed problems, herbicides are available for integration into the program. There are non-toxic herbicides available to use in most cases. Vinegar works very well on puncturevine. Whenever possible, apply herbicides as spot-treatments to the target weeds. Don’t just spray the herbicide everywhere and hope it kills something Spot spraying will reduce human exposure and helps to protect non-target vegetation and beneficial soil organisms that can be damaged or killed by herbicide residues. If Roundup or Ranger Pro have to used (and they probably don’t), then use a colorant to mark the treated area. This will not only insure proper coverage, but will help a passersby see and avoid the treated area. Do not allow children or pets to play or lie on the treated area. It needs to be roped off and a sign posted that identifies the herbicide.
If cities and counties use these methods; touring and identifying weedy areas, using solarization where possible and spot treating with herbicides where necessary, it will be a lot more cost effective than just spraying toxic herbicides everywhere and it will be a lot safer for the children and all citizens, which is the primary reason for adopting this kind of program.