Her work is defined by bold, black outlines and a flattened perspective that suggests the influence of Japanese woodblock prints. Unlike many of her contemporaries who favoured soft, hazy washes, Harrison used pen and ink to create strong graphic structures. She frequently used a palette of deep blues and forest greens. In The Big Spider's Diamonds, her ability to combine whimsical subjects with a slightly dark, medieval aesthetic is apparent. She focused on the physical weight of fabrics and the geometry of the natural world rather than realistic depth.

Modern collectors value Harrison for her ability to bridge the gap between Victorian fairy painting and modern graphic design. Her illustrations possess a clarity that works well in contemporary interiors, offering a balance of decorative detail and clear composition. The narrative quality of her work provides a sense of story without relying on overly sentimental imagery. Her prints offer a way to bring the aesthetic of the Arts and Crafts movement into a home through a medium that is both accessible and visually striking.