Ron,

Here in zone 7, SE WA, my watercress
winters over in the pond just fine. It even
gets frozen in ice where it spills over the
waterfall into the pond and survives just
fine, coming back first before any other
plants in the pond.

kathy :-) www.blogfromthebog.com
this week's entry - aquatic snails
Pond 101 page for new pond keepers ~
http://hometown.aol.com/ka30p/myhomepage/garden.html