Azola and Duckweed Makes a Comeback

A very interesting thing has happened in the past month, some tiny plants have come back in force in the frog pond. I haven't purchased Azola or Duckweed for a couple of years but the seeds must still exist and when the conditions are right, it grows like crazy. The first picture shows a huge growth of Azola covering a section of the frog pond (with a couple of Duckweed mixed in). In the second picture is a neat looking batch of Duckweed just a foot away from the Azola in the first picture. These two plants look very different but cover the pond surface in a similar way.