They need fertilizing. Seriously.

How is their color? How long are the roots relative to the tops. If they are sort of olive green with long roots they probably need potash. If the color is a pale sickly yellow with dead parts on the older leaves and floats, they are chlorotic, and probably need iron.

If it is none of the above, please describe the symptoms, and I'll do my best.

I've seen it advised to take them out of the pond and float them in a baby pool or large buckets of water with Miracle Grow for a few days. Then rinse off and return to pond. The off-sets are baby plants and will eventually grow to full size.

WH also likes to be crowded to bloom well and some folks use hula hoops to contain them or tie off an area with string rather free-floating hilly nilly about the pond.

I've found them bloom best in a nasty, nutrient laden over warm body of water which is not what we want in our home ponds.

larryl,
Roots are about as long as the tops or just a tad longer, color is pale with dead parts on older leaves and floats.
Hope this helps. Aside from the WH other plants (besides lillies which are fed separately) are not doing all that great either.
Thanks again, Larry

It sounds like an iron deficiency. You should also see some veining on the leaves. It will have green veins against the pale yellow green background. The newer growth will be the palest with less veining. Healthy WH also have some slight veining, but it is dark green over a medium green.

For an iron deficiency the best product is Fertilome Liquid Iron which contains chelated iron and other micronutrients. It isn't specifically made for ponds, but I have used it for years with good results. For 2700 gallons add two or three ounces to the pond water. If the problem is iron you should see some improvement in the color of the WH in a few days.

If you want to try the shotgun approach, you can add some potash too. It won't hurt a thing even if the problem isn't a potash deficiency. Add a handful of potassium chloride or potassium sulfate. The best, and cheapest, source of potassium (AKA potash) is a special kind of water softener salt that is intended for people on extreme low sodium diets, so it is potassium chloride instead of the usual sodium chloride. I get mine at my local Grange Coop.

The proposal to put your WH in buckets of Miracle Grow would work, but it is a lot more effort if you have more than a few WH. It is far easier to correct the deficiency for the whole pond and be done with it.

larryl and comettose,
Thanks for the help, will try the shotgun approach. My plants look like what larryl described and i think his approach will most likely fix my other plants as well.
Thank you all,
Larry