Penstemon baccharifolius

From 2000 to 7000 feet of elevation, rocky slopes, limestone crevices and bluffs, and seemingly soilless cracks in limestone ledges provide the required sharp drainage for Baccharis-leaf penstemon in the Edwards Plateau and Trans-Pecos of Texas and south into Mexico. This densely branched subshrub with herbaceous growth above becomes woody at its base. It may be erect or somewhat sprawling. It's 1- to 2-inch-long, thick, smooth or fuzzy leaves show small teeth along the margin. Inch-long straight tubular scarlet flowers open along the stalk from spring through summer.

Baccharis-leaf penstemon makes a desirable rock garden plant given excellent drainage and roots shaded from the late afternoon sun with mulch or rocks. It may die to the ground in winter or need to be strongly cut back to promote a bushy habit.