Curly parsley, Petroselinum crispum, is a familiar garnish used in restaurants. Although it is a biennial, you will have better luck if you sow fresh seed each year. Parsley seed is slow to germinate, so it is recommended that you soak seed overnight in warm water before sowing. Curly parsley grows close to the ground, so use a light mulch to keep the plants from getting spattered with mud.