The faintly scented flowers of Viola decumbens may be blue, purple, violet or white. They nod on long stalks, growing solitary from leaf axils near stem tips. The sepals are long, narrow and pointed, red or green in colour.

The corolla is two-lipped and five-petalled. The lower petal, not paired and rounded as the others, is smaller, keeled and dark. There is a tubular spur growing from it. An orange (sometimes yellow) marking in the flower centre is occasionally present.

Flowering happens from midwinter to midsummer (Manning, 2007; JSTOR; iSpot; Privett and Lutzeyer, 2010).