Penstemon ( Castle Forbes Penstemon )
The genus Penstemon is made up of 250 species of deciduous , semi - evergreen , and evergreen perennial and subshrub , and numerous cultivars which tend to be semi - evergreen . Leaves are narrow , up to 3 inches longsighted , or large and ovate , to 5 in long . Racemes or panicles of foxglove - same flowers are produced from former summertime to mid twilight . ‘ Castle Forbes ’ bears ashen - throated , bright rose scarlet flowers ....