Cosmos is for me a sign of approaching winter. If you drive on the roads on the Highveld of South Africa, then you will see these colourful flowers. They flower late summer to late autumn, so it is roughly February to April.
There is a Cosmos Route - you just drive in the direction of Secunda and then you will see these masses of colourful flowers.
Historians believe that the seeds of the cosmos flowers were brought in with bags of feed for English horses during the Anglo-Boer war. Cosmos is native to Mexico, where most species occur. They also occur in the US, Central and South America.