The hairy foliage and habits suggest that it might be an Oriental poppy (but flowers are needed in order to make a firm ID). Oriental poppies are perennial. They do not like hot weather and all of the foliage can die down in the summer months, with new growth appearing in the cooler seasons. Annual poppies from this spring would have died down by now (they grow each year by seeds and live for just one season). Annual poppies can sprout and grow from seeds in the fall, but in cooler weather than what we have right now.

You can leave this plant in the ground. It is possible that it will bloom next spring if it's in a good position in full sun with well-draining soil.
Christa