Posted: 06/08/2017 at 12:28
Plants take time to establish and to grow. You've taken the sensible option of spacing them to give them root to grow, but the downside is that there is currently space for weeds to develop. As we all know, Murphy's Law states that things you don't want will intially grow much faster than those you do want.
All you can do is weed regularly, water and feed well, and mulch to suppress the weeds. In time, and it may be a couple of years, the plants will expand and greatly reduce the weed problem.