What kind of plant does Jem destroy in Mrs. Dubose's yard in To Kill a Mockingbird?

Jem's punishment was that he had to read to Mrs. Dubose every week.He learned about her morphine addiction,and was very sad for making fun of her and being rude to her because she was actually quite nice.In the end,Mrs. Dubose dies,and leaves Jem the candy box that was in her home,and inside was one of the flower tops that had grown back after Jem had cut all the tops off.
Jem had to read to Mrs. Dubose after school everday and on Saturday. He had to do for two hours and for one month.