All parts of penstemon strictus
are essentially hairless apart from the curved, white stamens which have a sparse covering of short hairs at their tips, around the purplish anthers. Stems are thick, straight, rigid and unbranched, up to 2.5 feet tall, bearing small clusters (usually 2, sometimes 3 or 4) of bluish purple flowers at the upper nodes. The corolla is just over an inch long, opening to two upper lobes and three lower lobes, purple in color, more bluish along the edges. The interior of the corolla is lighter colored, sometimes crossed with darker vertical lines. Flowers tend to form only on one side of the stem.
This is a common species of the foothills and lower montane zones, blooming for long periods during late spring and summer.