Weeds are only weeds when they are not yet domesticated or planted in containers for some use. Just like the Mimosa, which is an obnoxious weed here, is an ornamental in temperate countries. I see also in some blogposts that porterweed is also cultured in gardens.
Mimosa diplotricha or Mimosa invisa
Urena lobata or Caesar weed, flower size is about 1.5 cm in diameter. For botanical descriptions, medicinal values, and other names, and references, click HERE
Above and below: porterweed or Stachytarpheta jamaicensis
wild cosmos plants, Cosmos caudatus. This weed is supposed to be brought in by the Spaniards
This looks like a shrimp plant, but it remained green until it dries to brown. It is different from the common green shrimp plant in literature. But this is very drought tolerant and can still be seen with little greens even when most other plants turned brown in the dry season. Seeds are inside those structures, which might be bracts.
For the last plant, will anybody be interested to plant them as ornamental plants in their gardens? I am thinking of planting one in a pot at home, and if it will be pruned or trained, i guess it will be nice. Who wants green shrimp plants? Me!