One of the maintenance regimens the City manages is lake bank vegetation. The residential lake banks in Weston were built with designed safety slopes which result in 10-15’ wide sections of shallow water around the perimeter. These submerged portions of the lake banks, or “littoral shelves,” are ideal for the colonization and growth of wetland-dependent plant species because they allow plants to anchor to the substrate and withstand wave action. The vegetation along lake banks, also known as littoral shelves, is necessary for water quality, enabling Weston residents and visitors to enjoy pristine water conditions. Diverse vegetation pulls impurities from the water, like a filter, and releases essential oxygen into the water and atmosphere. Aquatic plants are important for wading birds, like herons and egrets, as they provide shelter and support food sources, like small fish and insects. The City’s vegetation maintenance regimen intentionally preserves the healthier areas of native vegetation just for these reasons, promoting a healthy and sustainable ecosystem.

Unfortunately, Florida’s climate is ideal for a wide range of non-native/exotic plants, and sometimes these non-native plants escape the landscape, invasive plant or algae species sometimes colonize these areas, and undesirable growth of native plants also occurs at times due to high levels of fertilizers disrupting the natural chemistry of the ecosystem. Some of the plant species that grow in these conditions have undesirable, aggressive growth habits which can also infest the City’s permitted mitigation/conservation areas on the opposite shoreline. Therefore, they are considered highly undesirable and the City budgets resources annually to control this undesirable growth.

To control this undesirable/excess growth while simultaneously maintaining the City’s aesthetic character, the Public Works department utilizes well-researched groups of herbicides to effectively combat the unwanted vegetative growth. Residents often inquire about the spraying of vegetation along the lake edges or request to have “weeds” removed. The City sprays or treats the exotic weeds which die, fall into the water and slowly decompose, leaving only the native plants. Dead plant leaves and stems break down in the water to form small particles of enriched organic material.  These organic nutrients feed the phytoplankton which then feed small aquatic insects, shellfish and small fish that are food for larger fish, reptiles, amphibians, birds and mammals.  In rare occasions, physical removal of the offending vegetation growth may be an option for practical reasons or effectiveness.

The city contracts with experienced, qualified, and licensed aquatic plant management contractors to assist in treatment and management of this invasive/undesirable vegetation growth. These companies work tirelessly to decrease invasive populations and maintain the diverse ecosystem that was once part of the Everglades. The waterways receive quarterly herbicide treatments where nuisance species such as bladderwort, hydrilla, torpedo grass, cattail and Peruvian primrose willow are the main concern. The table below shows the typical chemicals used to treat these problem species; a link is provided for further descriptions of each compound.

TREATED PLANT SPECIES	IMAGE	CHEMICALS
Bladderwort (Utricularia sp.)		Diquat Dibromide; Copper; 2,4-D Acid
Torpedo grass (Panicum repens)		Glyphosate
Cattail (Typha sp.)		Imazamox
Hydrilla (Hydrilla verticillata)		Copper

Though concentrated herbicide ingredients sometimes pose a minor toxicity danger to handlers of the chemicals at the time of mixing or application, these herbicides are handled and applied in strict accordance with the labels for safe and effective use on target species of plants in their respective areas. When handling the herbicides, contractors are instructed by the manufacturer to wear certain personal protective equipment (PPE) in accordance with the manufacturer’s approved Safety Data Sheet (MSDS) in order to prevent potential injury or allergic reactions to the chemicals used. These MSDS standards are provided after registration of legal pesticides through the United States Environmental Protection Agency (EPA). Typically, herbicide applicators and handlers are recommended to use long-sleeve shirts and long pants, closed-toed shoes with socks, protective eyewear, and chemical resistant gloves to protect vulnerable parts of the body from possible harm.  In some cases, a respirator is also recommended. This full body cover may appear intimidating, but it is all for the safety of the applicator/handler of the wet or dry chemical ingredients which quickly become inert and non-hazardous to others after application.  Once they dry or chemically bind to environmental particles (usually in just a matter of minutes), the potential ability to have secondary effects on humans or wildlife is lost. The City also specifically avoids use of any herbicides with extended lifespans in water to ensure irrigation pickups in the lakes do not spread “live” herbicide into the landscape.  For those residents aware of or concerned by recent litigation and judgments against the herbicide Glyphosate and its manufacturer Monsanto (now Bayer) in California or other geographic areas, the following links may provide additional background regarding the specific circumstances and current position of the scientific and medical community regarding the safety of Glyphosate use:

• Journal Article 1
• Journal Article 2
• EPA Website
• NPR / WLRN

As previously mentioned, the goal of herbicide usage is to preserve the native vegetation found in South Florida before the introduction of harmful invasives. Invasive plants compete with the native species, ultimately decreasing their populations if left uncontrolled. This results in decreased biodiversity and reduces habitat and food availability for the wildlife that is dependent on those native host plants. The City’s contractors use several methods to remove invasives, prioritizing more targeted methods including hand-pulling and hack-and-squirt (where target species are cut, and herbicide is applied directly to the stem). However, more aggressive species, such as torpedo grass, require broader application through the use of herbicide spraying. Herbicides are studied and tested extensively before being placed on the market, including evaluation of their direct toxicity, breakdown products, persistence in the environment, potential to accumulate in the food chain and hazards to non-target species. The herbicides used in Weston are specifically chosen for their specialty in wetlands, meaning they have been tested and are deemed safe to fish, birds, and other wildlife found in these ecosystems.