Viola odorata, the old-fashioned fragrant sweet violet, is a charming thing to grow, but to be honest, you and I will never grow enough sweet violets to make a liqueur from them. Grow them for your own amusement, float them in drinks, and then go buy violet liqueur. My favorites are Rothman & Winter Crème de Violette from Haus Alpenz, Crème Yvette from Cooper Spirits, the same people who make St-Germain, and Tempus Fugit’s Liqueur de Violettes.
The flowers are hardy to about -20F, prefer shade and damp rich soil, and respond well to being divided every few years. Look for ‘Queen Charlotte,’ a popular old European perfume variety.
The classic cocktail, the Aviation, was impossible to make until the aforementioned violet liqueurs came back on the market after a long absence. If you’re in the mood to experiment, try substituting any floral liqueur or syrup for the violet liqueur.