Can you build a flower pond and put a flower box?

You can't. It is not recommended to build a flower pond. First, the cost is relatively high, and second, the risk of roof leakage will increase exponentially. Of course, if you say 100%, it will be missed, which may not be true. Recently, I met two owners, both of whom were leaking because of too much water in the flower pond. One is a second-hand house just bought. The top floor and dining room are leaking. It keeps dripping when it doesn't rain. There are two rows of flower ponds and a big fish pond on the roof. There is a lot of water, and the drainage is not done well. After consulting my opinion, I tore down the flower pond and the pool. But the flower mud stayed, and I planned to plant it in potted plants or flower boxes after the roof was waterproof.