The leaves of purple viper's bugloss form in a basal rosette and lack stems. The initial seed leaves are rounded with short stalks. The first true leaves are also rounded and display a prominent central vein. Typically, these leaves are green and possess a slightly rough texture, aiding in identification. Mature leaves can grow up to 4 inches (10 cm) long, maintaining their rounded shape and displaying a distinct central vein with prominent venation patterns.

The flowers of purple viper's bugloss are trumpet-shaped, initially blue, then turning purple and finally pink. Each flower produces four brown or gray nutlet seeds surrounded by a bristled husk, giving them a fuzzy appearance. Typically, flowers form on one side of the stem without stalks. Of the five stamens, two are significantly longer than the other three. They don't emit a notable scent and bloom primarily in spring, with flowers measuring approximately 0.6 inches (1.5 cm) in length.

The stem of purple viper's bugloss is typically erect and robust, either single-stemmed or with multiple stems. It measures up to 3 feet (90 cm) in height and is characterized by its stiff, bristly hairs that cover the surface, offering a rough texture. The color is generally green, though the dense hairs can give it a grayish hue. Branching is common, with each stem segment thick, approximately 0.5 inches (1.3 cm) in diameter at the base, tapering towards the tips.

The fruit of purple viper's bugloss is comprised of a cluster of four nutlets, each displaying a distinctive three-angled, oval shape. These nutlets exhibit a muted palette ranging from gray to brown or even black, with the surface characterized by a network of fine wrinkles and noticeable pitting. Each nutlet's texture and coloration are significant identification markers that can help differentiate this fruit. The dimensions and hues of these nutlets might vary slightly, but they consistently maintain their unique angled oval contour and textured surface.