Still need help, Questions about Pond Plants............

Well not too many people posted to my last question, but thank you to
the three who did However I'm still confused, I went to look for pond
plants at Walmart and home depot as someone suggested, and I now
realize that the plants are not in "water", but soil So can I just
take these plants and shake all the soil off then put in my pond? It
seems they would die? I did find a list of plants to try. Also what can
I use as "soil", pond soil is very exspensive, 6.47 for a small bag?
I also have just a few questions about my filter, what else might a
place like home depot call a Bulkhead fitting? I just couldn't find it,
maybe this is the wrong kind of store?? The person I asked said that he
hadn't heard of it?? And I didn't see anything there like the online
picture. About the lava rock, I got a bag of this today and it's very
small like gravel, and very heavy? It's the only one they had, but I'm
not sure how this would stay out of the sediment area of the filter?
Sorry for the confusion, but I'm very new to this and have no clue when
it comes to pond plants. Ouida