I remember reading a book in the 80s about a girl who makes a wish on a wishbone that her house inside becomes filled with grass, plants, etc. Her wish comes true and gradually her house is filled with nature but then it becomes out of control. She has to use the wishbone to break the wish. Its more of a chapter book for younger readers but I still would love to find anything about it. A second reader is looking for this one and remembers the following deatails:
I agree, it must be for younger readers because I think I read it at age 7 or 8 (also in the 80s). The only detail I can add is that I think it had very detailed pencil sort of drawing illustrations. And I think maybe the main character’s name was Meg.
Solved by Lost Classics reader Jenny: Gertie’s Green Thumb by Catherine Dexter
Lost Classics of Teen Lit: Name That Book! 