I spent a couple of hours sorting out the pickerel weed I had in the pond and have divided it into several largish pieces, including the long leaf stems. I've potted up two and put them back in the pond. It is a very good and attractive bog plant and is supposed to grow well at depths of up to 30 cm (12"). My plant didn't seem to know that and grew extremely well at over 2 feet deep .
If anyone wants a chunk please let me know. I think I'd have to cut the leaves off for mailing, otherwise the package would be too large and then the plant should be potted up and kept very moist till new foliage appears before planting it out.