Lake Lawrence Noxious Species
Fragrant Water Lily
The primary noxious plant in Lake Lawrence is the Fragrant Water Lily. (Fortunately, Eurasian Watermilfoil is not a problem at Lake Lawrence.) These water lilies grow in dense patches, crowding out native plant species. Mats of water lilies create low-oxygen areas that harm fish. These mats also make it difficult to water ski, swim, fish, or even paddle a canoe. Although relatively slow-spreading, water lilies will eventually colonize shallow water depths to six feet deep and can dominate the shorelines of shallow lakes. One plant rhizome can cover about 15 feet in 5 yrs.
From 1990-1994, the Lake Lawrence Management District sought to control water lilies by manually digging up the plants with a county-owned backhoe mounted to a barge. In 1996-97, the LMD paid for a herbicide application to control some 80 acres of water lilies. Two follow-up spot applications were performed in 1998 and 2000. The LMD contracted with a commercial applicator to treat the lilies twice a year in 2003-2004 in order to continue with its eradication efforts. In 2003 over 98% control was obtained on the approximate 2 acres mapped.
Yellow Flag Iris (Iris pseudacorus)
Another noxious plant in Lake Lawrence is Yellow Flag Iris. Yellow Flag Iris is a fast-growing and fast-spreading invasive plant that can out compete other wetland plants, forming almost impenetrable thickets, in much the same way as cat-tails (Typha) do. The Integrated Aquatic Vegetation Management Plan for Lake Lawrence addresses control options for this plant. In the mean time homeowners are being asked to dig up this plant if sighted on their property.
Property owners can do their part by not introducing any type of plant to the lake, especially when cleaning out fish tanks. Undesirable plants can create a long-term problem that is expensive and difficult to control.
Staff contact: Janie Civille (360) 786-5830. E-mail: firstname.lastname@example.org
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