Williamson Pond, Columbia
Williamson Pond Species Map
Transect Data | Water Data
Williamson Pond is a 0.1-acre privately owned pond located in Columbia, CT. It was surveyed in August of 2008 based on a tip that it might contain the invasive species yellow floating heart (Nymphoides peltata). The last documented report of this plant in Connecticut was in 1900.

The invasive species, yellow floating heart was found along with parrotfeather (Myriophyllum aquaticum) and six native plant species. Yellow floating heart covered over 95% of the pond and was extremely dense. Parrotfeather was very sparse and only occurred on the south-eastern shoreline. This is the furthest north parrotfeather has been found by CAES IAPP and indicates it can survive the winters in most of the state. Marsh primrose-willow (Ludwigia palustris) was found bordering the edges around the pond and snailseed pondweed (Potamogeton bicupulatus).
Species recorded in our 2008 survey of Williamson Pond.
Scientific Names
*Invasive Species
Marsh primrose-willow Swamp smartweed
Parrotfeather* Water plantain
Snailseed pondweed White water lily
Spikerush Yellow floating heart*