Water Chestnut: A Growing Problem

 

Water Chestnut will grow in thick
masses that can overwhelm a pond
or river in no time.

Water Chestnut is the most invasive weed I have ever seen.  And, it is taking over, or should I say overwhelming,  many carp waters in this state. This weed looks leaves from a tree in the water.  It grows up from the bottom with the leaves appearing on the surface.  Under the leaves you will find multiple seeds that fall off in fall and seed the bottom for the following year. One of these plants can produce anywhere from 10 to 20 seeds. The seeds eventually turn into a black spiky seed that has sharp points. So, you can see how this weed can multiply in huge amounts from year to year.  I was reading one article that stated in one lake the weed went from covering one acre of water to 100 acres the following year. It can spread that fast! It will destroy native plants and suck the oxygen out of the water posing a threat to fish.

There are only two ways to get rid of it- pull it out by hand or treat with chemicals.  I have seen an army of kayaks and canoes in one location trying to pull it out. Thirty boats working all day barely put a dent in it.  As one volunteer told me, it's like shoveling sand against the tide. Supposedly chemicals are coming next for this place.

I have seen this weed in multiple places in RI, and where it grows, it has shut down the carp fishing.

 

Under the plant's leaves  you will find seeds 
growing.  One plant can produce 10 to 20
seeds that will grow next year.

Here's a lake completely inundated with water
chestnut weed.  Two years ago there was NO weed 
in this location. If unchecked it will take over a lake.