I believe that the Forget-Me-Nots don't like that deep/depth of water. Maybe once they are well established but that sounds like what happens to young plants when placed too deep.

I had a couple of Fiber Optic plants that looked great at the garden store and they said that they could go into a pond up to several inches with water coverage. I think I had six plants, and five of them I put into the margins with two inches of water coverage, the other single plant I left out of the pond. Now what do you think happened? The FiberOptic plants in the pond all died before I could do anything about it and the one potted plant, now a terrestrial plant, is thriving.

Also, you said you used "a general fertilizer." I'm not sure what that is but if it is like an all-purpose Vigoro or Miracle-Gro then I think you might be harming your water because of the form of N-P-K you're adding. You might want to stick to water gardening fertilizer "tabs" available where pond supplies are sold.

Maybe someone else with more Forget-Me-Nots experience can reply... but all in all with the other plants thriving, I think you're really close to a good balance -- but just too deep with the young plants.

Good Luck!!

This is my first year for Water forget-me-nots but this is what's working for me. I read they like moving / shallow water so I washed all the dirt off the roots and put them in the stream in the gravel, in the full (zone 5) sun. They are doing great.

I'd suggest taking it out of dirt and putting it in a pot / basket with lots of holes - filled with gravel. Bury it almost up to the leaves. Then put it in the water just deep enough to cover the gravel.

I think it grows like watercress - anything above the water has leaves, anything below the water grows roots and takes nutrients from the water.
sam

I've had blue aquatic forget me nots for years in my fish pond. They were originally potted in a mesh pot with pea gravel in it at least three inches under the water. Over the years they escaped and have colonized the entire pond growing in free floating mats and in other pots and among the rocks on the edges and bottom in the shallow end. They are in mostly full sun and I've never fertilized. They bloom for months. I sell extras on eBay because they'd take over the entire pond if I didn't thin them out. They occasionally get aphids but are otherwise trouble free.

I did have trouble with the white and pink, they both died.

Thank you very much everyone!

Pondbucket - It was a general aquatic fertilizer, not Miracle Grow or anything. They had all sorts of "specialized" fertilizers for lilies and things, this stuff [of course I can't find the box now] just said "all purpose." It's a granule, yellowish..? So not helpful, I know.

Since I posted, it's starting to thrive some. Loads of roots are on the clay's surface and going through the the gravel, so I suppose that's a good sign. There's lots of new growth continuing to coming in, too. It's all concentrated lower down on the "older" stems and the "older" leaves/flowers are wilting and dying off, but the new stuff is bright green and getting some flowers. I tried to prune it a teeny bit, just to get the dead bits off, and it repaid me by having that entire stem die back. I put my shears away after that and have decided to let it do it's thing. Honestly I'm afraid I'll kill the darn thing and have to go buy another one just to have to baby it to death, too.

If it starts failing again, though, I will most definitely try the mesh pot with gravel instead of dirt. It's supposedly a perennial here in Georgia, so hopefully I'll have next year to try and not kill it. :)

Thanks so much!