City of Lawrence                             

Parks and Recreation Department



Fred DeVictor, Director



Mark Hecker, Park Superintendent



Crystal Miles, Rowan Green






Pesticide Free Park Status -Watson Park



In June of 2005 the City Commission directed the Parks & Recreation Department to implement a pesticide reduction plan in the City’s parks and to select one high profile park to manage using a pesticide free management plan.   Buford Watson Jr. Park was select for this pilot program. In addition to this high profile park, 33 other lower profile City parks were classified as pesticide free.


In Buford Watson Jr. Park citizens volunteered for a combined 75 hours to remove weeds in the landscape beds.   This was in addition to 586 hours of parks and recreation staff time spent in the park on landscape maintenance. I think all would agree we were able to maintain a reasonable level of quality in the park landscape beds by using good cultural practices and our combined city work force and volunteers.    


Alternative products and techniques were also used in this park by staff as a substitute for the chemical pesticides and herbicides that have been used in the past. These techniques and products had varying degrees of success. The following pages show some examples of products and practices that we have tried.


Weeds on hard surfaces, such as sidewalk cracks, were successfully removed with the ‘Flamer Machine’. This highly effective method both killed the plant and burned it away.  Staff felt that the main disadvantages for this type of application were the discoloration of the sidewalk; the machine was cumbersome and required two people to operate for any length of treatment area; the sidewalk was left heated for 15 minutes or more, which meant no one could enter the work zone barefoot.  This became an issue due to the pilot project location in the same park as the outdoor aquatic center.  Because of the high heat factor, the machine could not be used in a close proximity to parked car tires, such as curbs.  So these areas would need to be posted and cleared of cars prior to setting up the work zone. The Flamer machine methods appears to have merit for use in several locations with less pedestrian traffic.  Again, this is only a cleanup technique, with no residual to treat future weed populations. 


A second alternative product was used as a natural substitute for chemicals.  The product was naturally derived Horticultural Vinegar (20% acetic acid).  The vinegar product was applied on 3 occasions in Buford Watson Jr. Park to control weeds near signs, fences, benches and in landscape beds. The product had only limited success on these weedy locations and was not effective on a long term basis.   Product information suggests best success rates for this product is to  apply it in the heat of the day, which during the summer would most likely be when the park and neighboring swimming pool were at their busiest time and not a suitable time for staff to be making these treatments.  The product only burned the weeds, resulting in a re-growth within 14 days. Additionally, the acid in the natural vinegar product’s posed a higher risk to staff for eye, skin and respiratory problems than the previously used chemical product (Round-up).   The horticultural vinegar did not carry a label for applicator directives and personal protective equipment, which is a concern of and for our applicators.  However we did locate a label for Bradford vinegar that has the same basic chemical make-up as the other product that carries a EPA pesticide label, which would seem to indicate these products may not be as applicator friendly as originally thought.  


Going into the winter and early spring, we stepped up our normal Mulching cycle in an attempt to compensate for the lack of a chemical pre-emergent weed control in the bed areas. This cultural practice will work to a point but eventually mulching at this rate will have detrimental effects on the plants in the beds and the decomposing woodchips will need to be removed to restore a good growing environment in the beds.


Last year one of our horticulture staff was vacationing near Carlboro, North Carolina and stopped to talk with their city staff about the Wapuna Machine we had heard they were using.   The Carlboro, NC staff person did not recommend the City of Lawrence purchase or utilize the Wapuna machine. They felt it was too expensive to purchase and operate and was only marginally successful. They had pretty much discontinued use of their machine. 


One of the most difficult weeds in the park that causes unsightly growth in the landscape beds and in turf areas is Bermuda grass.  This invasive perennial weed has an extensive root system which robs other desirable plants of needed growing resources and allows the plant to survive non- herbicide products.  Applications of the vinegar only burned off the top foliage, achieving no significant long- term control.  We believe the Bermuda grass population in the park will continue to be a concern. In 2005 large areas of Bermuda grass were remove from the park with a sod cutter and reseeded with desired turf species, in order to fight back the encroachment into undesired areas.  This practice is a very labor intensive approach to this issue (approximately 60 man-hours), but alternatives are few in treating this weed without herbicides.  


We continue our Integrated Pest Management practices to monitor for insect infestations on susceptible target plant population in all parks. In Watson Park we removed one diseased pine tree, manually pruned targeted shrubs to reduce insect populations and reduced the size of one weed infested landscape bed.    We also used  a non-pesticide bio-product to treat insects that were damaging  screening hedges by the swimming pool.  


In all parks, a new application signage system was implemented to comply with the newly revised policy, increasing the length of signage time for pre-treatments and post treatments.   The signs posted the date of application, product name, active ingredient,  reason for use,  and product labeling “caution” information by the applicator. These signs were used at park entrances and spaced at frequent intervals in the treated area to notify the public of application activities. They were set out one hour in advance of any treatments, and removed after treatment.    Field observations by staff and interaction with general park patrons suggested positive attitudes towards the signs.  The public appreciated the information, although some park users (over 10) verbally stated the signage was unnecessary prior to any application.   Many stated they thought it was unnecessary to post for a product available over the counter to any homeowner. On some of the right of way areas and street medians, staff would like to see the signage distance increased to 300 feet. We feel signs were not really being noticed, very little pedestrian traffic enters these sites and the extra work did not seem effective.


 Our concern continues for at-risk landscape plants  in areas under high heat and drought stress. These circumstances often attract insects and the plants are not healthy enough to outgrow permanent damage. Roses and rose gardens present significant challenges.   We would like to be able to pursue bio-rational products considered “non-polluters” in a rotation  to treat these types of difficult problems.  Some of these products might be Neem Oil and Armbicarb and others with minimum risk active ingredients. 



Our biggest challenge in attempting to manage any park pesticide free is finding an acceptable alternative product to replace the non-selective herbicide Round-up. This chemical has been used in the industry since the 1970’s and is considered to be a safe product for the applicator. It is the most cost effective way to control unwanted vegetation in parks and landscape areas. One gallon of Round-up costs $1.05 per gallon and controls weeds for 3-4 months. One gallon of horticultural vinegar costs $12.25 and only controls weeds for 2 weeks. Without this type of product we would need to fund and reinstitute string trimming crew for each of the park districts and develop a large crew of staff to pull weeds in landscape beds. We would not only have the staff costs, but also would need to provide vehicles to move them from park to park. We haven’t had to use these types of crews since the 1980’s because we have treated these areas twice a year and did not have to worry about weekly maintenance. It would seem unreasonable for the City to count on volunteer labor (75-100 hours per park) to perform these additional weeding duties, since the leaders of the existing group have indicated this will be their last year obtaining and coordinating volunteer efforts at Watson Park.



We have not yet completed a full year of the pilot project, but thanks to volunteers, we have been reasonably successful to this point. With the assistance of these volunteers, we are prepared to continue the program at Watson Park. The spring and early summer seasons present the most significant weed issues in park management. I would like to see how we are able to handle these seasons before attempting to add more parks to the pesticide free list. I feel that adding more high profile parks to the pesticide free list would require a substantial long- term financial commitment by the City. We were able to absorb the added operational costs to maintain Watson Park as a pesticide free park, but we can only stretch existing dollars and staff so far, before we start showing a decline in the quality of our park system.