Roadtrip - if you're planning to shade out the milfoil with a fertilization program, you should know that both Eurasian watermilfoil and Hydrilla are two exotic plant species that require minimal amounts of sunlight (compared to other plants) in order to thrive. It is their tolerance to low-light conditions that allow these two species to rapidly displace native plant populations. So, it is highly unlikely that you will control an existing EWM population through efforts to reduce water-clarity.

Also, EWM has a very high tolerance to cold temps - actually growing under ice in many regions.

The original posts on your pond (Oct/'03) covered several treatment options. And your dose-rate question earlier this month indicated that you were considering a herbicide treatment (though too late this year). What prompted you to pursue a fertilization program in hopes of controlling the EWM?

BTW: fertilizing a EWM infested pond will likely prompt a significant filamentous algae explosion. These types of algae normally orginate on (attached to) the bottom of clear ponds where abundant nutrients are present. However, if EWM is already growing within a few feet of the surface (though the depth may be 10+ feet) filamentous algae will treat the ceiling of EWM growths as the "bottom" and spring forth from that "elevated platform".

Kelly Duffie
Cypress, TX