Dylan, I have just recently did battle with Hydrilla in my pond. I can tell you that Hydrilla is extremely invasive. The first year I noticed the Hyrilla it was not that pervasive. The second year the Hydrilla had taken over the entire pond. With the Hyrilla already mature my choices were limited, I choose and applied Aquathol. The Aquathol provided a slow kill, almost 4 weeks, but it did eventually work. This year, having done my due diligence, I used Sonar. My results are posted in the thread below.
http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Number=171679#Post171679The Aquathol provided a topical burn down of the Hydrilla. The Sonar, being systemic, is supposed to provide a longer term of control. The longevity of control in my case is to be determined.
I can tell you this, do not let Hydrilla continue to grow. It will take over the entire pond. I have never seen anything grow as fast as Hydrilla.
Ron
