Years ago I purchased a couple of those water lilies and chucked 'em into our little pond and they did outstanding. I had lovely blooms the very first season. Although it was so long ago, I don't remember what time of year that I had purchased them or what type they were.
This past March I bought two more lilies (one a Sioux, and another that I lost the tag for), as well as a black gamecock. It was just days after Lowes had set up that product display, so pretty much every cup I picked up had moisture inside and/or greenery already popping up. I placed all three into our pond, just as they were, even though it was still cold out. As soon as the weather started warming up they all sprouted, and all are still doing well. I shoved a little piece of (no copper) aquatic plant fertilizer into each coconut ball/pot too.... The gamecock didn't produce flowers this season, but the stalk looks great and I will be potting it soon. I did pot one of the lilies, and I'll pot the 2nd. whenever I can find another container. Neither of the lilies have buds or blooms yet, but that's most likely due to my partial shade location. I'm just happy for the pads, and so are the frogs!
But just as others have mentioned, at this point in the season, I might be leery of purchasing any cups that look like the contents have dried up.