Another of my wild collected introductions, Senecio inaequidens is a weedy plant in its native South Africa, but those same characteristics make it a reliable self sowing annual in New York. It starts producing yellow daisies under an inch in diameter in June from self sown seedlings, but really comes into its own in September as flowers multiply on the rapidly growing plants. The flowers resist light frosts so they add welcome color when most other flowers are down for the count, usually sometime in November in our climate.
During an exceptionally mild El Nino winter back in the 90's, plants did come back from the roots both in the Bronx and in my Tuckahoe garden, so it might be a hardy perennial in the lower reaches of Zone 7. Nonetheless it reseeds profusely, so it will always be back, but fortunately excess seedlings are easily pulled so that it is no problem to keep it under control.