Primrose, Texas

Shrubby primrose or Texas sundrop (Calylophus drummondianus), a native of the parched southwestern plains, is the kind of plant that not only grows well areas of high heat and drought The half dozen species of Calylophus are all similar with woody bases and herbaceous stems.  Most are found in the southern Great Plains region and adjacent areas in Mexico. The gray-green leaves of this species are willow-like but only about one-eighth inch wide and to 2 inches long. Texas sundrop grows about 18 inches tall and 24 inches wide. Plants are mostly evergreen with only the slender stems and tips of the branches dying during hard freezes. Near the ends of the slender branches plants produce large, four-petaled yellow flowers to 2 inches across that open in the evening and fade away late the next afternoon. Peak bloom is usually in late spring but plants continue to flower whenever enough rain comes to cause new growth.