The flowers are trumpet-shaped, 4–9 cm (2–4 in) in diameter, most commonly blue with a white to golden yellow centre.

[7] It is rumored that I. tricolor seeds are coated with a chemical that induces sickness so as to dissuade people from using them as a drug, but this is probably a rumor that stems from several factors: - I. tricolor seeds, by themselves, induce sickness as a result of glycoresins[8][9] and the very ergolines that are desired by users.

[10] - Such is done to other commonly available substances that can induce effects, specifically gas dusters and acetone (which have bitterant added) and denatured alcohol.

- Chemical coatings are added to garden seeds to prevent fungal growth (e.g. neonicotinoids, Thiram, and ApronMaxx®).

[12][13][14] This shift, from red to blue, is induced by chemical modifications affecting the anthocyanin molecules present in the petals.