Pond plant growing media

Question:
Are there pond plants that do not require any dirt/growing medium.?
I bought a 'drop in plant"  at Home Depot.  Just drop the plant enclosed in the net and it will grow. They just had one like that. Are there others that I don't have to plant in pond potting soil that I can just drop in the water. I have a 60-gallon whiskey-barrel type pond.

Answer:
No pond plant really needs potting soil. We use it because it's handy and we are used to using soil. You can use any medium to hold the plant in place. It derives its nutrients from the water, not the soil. I have seen rockwool used, kitty litter, sand and rocks. The only general rule is that the top of the pot is about 1" below the water surface.
Your plant was in a growing medium in the net.  You just couldn't see it.