I'm building a pond (approx 9,000 gallons) and plan on planting a weeper next to it. Something about ponds and Weeping Willows just go great together...but....I don't want the tree to send it's roots sraight up thru the bottom of my pond, either. (If the liner gets a small punture, the tree will ensure it becomes a gaping hole in no time.) I notice alot of Weeping Birch trees in this area of Montana. I'm assuming they are native because some of them are absolutely enormous!!! Surely they've been around long before landscapers came to this corner of the world. I find them beautiful, stately tree's, that do have that droopy, weeping look, perfect for a pond. I'm not have much luck finding info about them on the web, tho. Maybe they aren't called Weeping Birches. Maybe that is just the comman name everyone around here has nick-named them because nobody knows what they really are. Anybody have any input? Thanks.