I'm seeing oxalis, eclipta, Rumex, and some that I can't enlarge the picture enough to make out.
Very important to know what you are dealing with.
The oxalis would definitely be the most difficult to clean out... Whether it has bulbs or is just extremely seedy, that is one successful plant...
Chickens really like it at my house, so... It has positive attributes.
Please tell us what kind of mulch you used when you set the bedding plants out...
All I see is annual vinca (Madagascar periwinkle).
Also... Did you till the existing soil? Or use potting soil?
I'm wondering if the seeds came with the soil mix... Not seeing them in the rest of the island.
