The watercress has taken over the container and the cannas that I planted in the center have stopped growing. Can I harvest the watercress leaves nearest the center to give the cannas more light? Would this help at all?

I wish mine would the leaves are great but it's time for some blooms lol. Definitely next year I will have a bunch of shallow rooted early spring bloomers. This waiting is terrible. And the watercress hides it's blooms underneath the leaves so I have to dig for those lol. One nice thing though the watercress has started to put out long stems so that I will get the drape affect I was going for.