Invasive - Eradicate!
Native to South and Central America, Water Primrose was introduced to the USA. It grows along the margins of lakes, ponds, and rivers, forming floating mats at first. By summer it becomes slightly woody, forming stalks that will flower above the surface.
Water primrose was likely brought to the U.S. as an ornamental plant. It now ranges from New York to Florida, west to Texas, and along the west coast. Primrose produces abundant seeds that are very small. It will also reproduce by fragmentation; roots will readily grow from the nodes.
Dense growths of water primrose provide breeding areas for mosquitoes, and will degrade both water quality and habitat for fish and wildlife. It fouls intakes used to supply municipal drinking water and irrigation, and becomes a navigation hazard. Creeping water primrose should never be introduced to open waters.
Creeping water primrose is a perennial plant that stands erect along the shoreline but also forms long runners (up to 16 feet) that creep across wet soil or float out across the water surface. The leaves vary from green to red tinged. The plants flower yellow in all seasons except winter. The yellow flower is very distinctive of creeping water primrose. Flowers vary in size from 1 inch to 2 inches in diameter.
Hints to Identify:
You can identify non-native water primrose species by their sprawling growth habit and showy yellow flowers. Look for the following characteristics:
- Bright, yellow flowers; normally with 5 petals
- Alternately-arranged, slightly hairy, willow-like leaves
- Dense sprawling, tangled mat of vegetation
Homeowner Treatment Options
|*Aquatic Biologists recommends implementing preventative management techniques and physical removal prior to, or in conjunction with treatment.|
Common Application Questions:
Q. How much should I treat?
A. The entire population should be treated as creeping water primrose is not native to the United States.
Q. When is the best time to treat?
A. Once water temperatures are around sixty degrees or warmer.