I found more info.( source Flora Argentina in Spanish): It is a native annual ( therefore a worthwhile wildflower in a prarie garden) in central, and northern parts of Argentina, also contiguous Uruguay, Paraguay, Bolivia and Chile. I suppose that it is hardly improbable for it to survive in the cold regions of Patagonia. I'm supposing that it would have naturally dispersed here. Still with its intruding capacity I would be cautious.
