Mostly found in an intense scarlet color, plants with pale yellow flowers are found in Beijing Shi and are called P. maximowiczii f. flaviflorida. Where the color forms meet, hybrids of a salmon color can occur. Has been hybridized with P. handeliana in cultivation. Closely related to P. tangutica. Dark purple plants from East Tibet formerly P. maximowiczii var euprepes are now P. advena var euprepes.