Primous... you are free to mention the store that you bought the plants from. That's acceptable, just can't use blanket statements about the store/chain/whatever.
Reporting a factual event like this is fine.
Such as, "I bought plants A and B from store X. I believe, that caused me to introduce snails to my tank, and here's the damage I believe the snails caused."
Just can't do this, "I bought plants from store X and they are such a terrible store. They don't care about their fish, plants or anything, and on top of everything else, they are overpriced. Their poor treatment of the plants allowed them to be covered in snails and now they ruined my tank."