Creeping Water Primrose
The water-primrose is a perennial aquatic plant whose long stems creep over mud or shallow water, sometimes forming dense mats which float on the water surface. Named for its yellow primrose-like flowers, while its long, oval leaves resemble those of willows. The water-primrose typically grows in slow-flowing rivers, marshes, ditches, streams and shorelines. As well as being able to grow in water up to 6 feet deep with its stems potentially extending 30 inches above the water surface. The water primrose is also able to colonize damp terrestrial habitats such as wet meadows.
Although it produces seeds, the creeping water-primrose spreads mainly with broken-off fragments of its stems easily rooting and growing into new plants. Its stems fragments may float away from the parent plant or be carried away by animals or humans. This plant grows very quickly in the spring and dies in the fall. Submerged or buried parts of the plant can survive the winter months and re-grow year after year. Early intervention and management to avoid large growth is the best prevention.
The water primrose can be cut and the roots can be dug up but physical control is difficult because it can reestablish from seeds or remaining roots. Physical removal when used in conjunction with chemical control methods will maximize success.
When used carefully according to the label instruction, aquatic herbicides can be safe and effective management tools. The products that have been successful in treating water primrose individually or in combination are Shore-Klear, and Reward. Cygnet Plus should be mixed in solution with herbicides when plants are treated.
Shore-Klear is a systemic herbicide that will translocate down into the root systems killing the plant. Successful water primrose management in heavily infested areas can take several applications.
Reward is a fast-acting contact herbicide, highly effective in treating the larger biomasses and root systems that had formed by mid to late summer.
Cygnet Plus is a nonionic wetting agent, sticker, activator and penetrant all in one. Cygnet Plus increases the effectiveness of herbicides uptake into the plant tissue.