Asclepias speciosa

Asclepias speciosa (also known as the showy milkweed or Greek milkweed) is a species of milkweed plant. It belongs in the subfamily Asclepiadoideae.  It is native to western North America.  It blooms from May to July.  This species is found in savannas, prairies, meadows, and fields.

Other websites

Asclepias speciosa at USDA PLANTS Database
Asclepias speciosa at Treatment from the Jepson Manual
Asclepias speciosa at Evergreen Native Plant Database

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