Yeah, it happens. Especially in old houses. Some tree saplings send up what look like vines that will find any window or crack in the foundation or, in a friend of mine's case, the hole left when they took cable TV out, and will grow right inside. And they literally grow like a foot a day sometimes.
It doesn't surprise me they were in Linda's place, what with the cracks and all that tasty tasty nitrogen in the carpet. (gack.)