What are the plants on?
The plants are on the barrier.
    src        edge_attr  dst
0     4               on   16
1     4   to the left of    7
2     6               on    7
3     7  to the right of    4
4     7  to the right of   14
5     9          wearing   11
6     9          serving    5
7     9  to the right of   14
8    13         watching    8
9    14   to the left of    9
10   14   to the left of    7