Amsonia tharpii is a species of flowering plant in the dogbane family known by the common names Tharp's bluestar and feltleaf bluestar. It is native to New Mexico and Texas in the United States. This plant is a perennial herb with a woody taproot. It grows up to about 20 centimeters tall. The linear to lance-shaped leaves are each up to 3 centimeters long and are whorled about the stem. The leaves lower on the plant are wider than those near the top. The white, pale blue, or greenish flowers are borne in clusters at the stem tips. They are tubular and about 1.5 centimeters long. The fruit is a two-lobed follicle. The cylindrical seeds are about a centimeter long.