Flowering Spurge (Euphorbia corollata)

Wikipedia entry: Flowering spurge grows in most soil types as long as they are well-drained. It is usually found in prairies, pastures, glades, and along roads and train tracks.[4] It has excellent drought tolerance and develops a deep taproot. It is difficult to transplant once established.[5]

Flowering spurge is native from Texas north to South Dakota and east to the Atlantic coast.[6]