Iron vines covered the photo of the boy. These vines don't wither away in winter, but instead entwine whatever they cover in purple flowers. The house was completely sealed in by these vines.
They were the chains that kept me locked inside the house.
The vines that bind my hands must mean that I'm still somehow trapped within that house.
If you can break the curse of that house, maybe the iron vines binding my hands will break as well.
Note
'Iron vines' is a literal translation of 鉄線 (tessen), one of the Japanese names for the clematis plant.