Tradescantia bracteata

Tradescantia bracteata, the longbract spiderwort, or prairie spiderwort, is a species of Tradescantia. It is native to the northern and central Great Plains and Mississippi Valley regions of the United States, from Arkansas and Oklahoma north to Minnesota and Montana, with a few isolated populations farther east. It is grown for its purple flowers. It blooms from May to July in the US.