I have some of my marginal plants in pots but last year I also put some right in the pebbles. I just thinned a lot of extra watercress and aquatic mint out of my stream and shallow beach area. I noticed the roots were wedged really, really tight into the crevices of some of the rocks. Is there any risk that the plant will push its way right through the liner? :o :unsure: I also have a few bareroot hostas, dwarf umbrella palm, and dwarf sweet flag in there but they don't seem to spread as aggressively.

Lindali, the only plant that I've heard that can damage a liner is iris.

I have lots of small plants in gravel over the liner and haven't had a problem. I also have some yellow flag iris in gravel over the liner that self-seeded itself there. That one, I am worried about. I cut it down a few times a year to keep its growth back. It's not really possible to remove it completely. These plants have been pot busters in my pond, literally putting holes in those black solid pond plant pots: yellow flag iris, common cattails, regular sweetflag (normally jumps the pot instead of busting it), and hardy canna. I'm sure there are others. I wouldn't worry about watercress or mints. They have smaller roots.

I don't think so. In my 5000 gal liner pond I have a reed bed at the back of my pond to aid in filtration when combined with my proper filters. The reed bed contains a lot of different large marginals, but most are one of the following: Greater Reedmace, Lesser Reedmace, Greater Pond Sedge, Lesser Pond Sedge, Bull Rush, Yellow Iris and Branched Burr-reed. Now some of these are getting very large and I have a considerable number of them, and their root systems are also large, but the liner is fine.

Thanks everyone for the input. I'll not worry too much, but I'll still keep an eye on the situation.