Around here, SE WA state, our nurseries seem
to get plants in May. But we are also experiencing
nice weather and I wonder if they will push the
season.

I plant watercress in my waterfall. I get it from the grocery store,
just a stem and leaves. I put the stem under a rock and
that's it. (Don't use BV's patent pending 'and beer' method
as I don't drink...) Watercress likes moving water and if the
rock will hold it in your fast moving waterfall it ought to do
really well. The roots don't require much of anything. When
I have to weed my waterfall I just grab it and it comes right
up, seems to send out very shallow and brittle roots.

kathy