P. somniferum grows 4 to 5 feet tall with long leaves that stand upright around a single stalk. The flowers, the largest of all annual poppies, grow to about 5 inches in diameter. Single, double, ruffled and frilly-petaled varieties are available, many with a contrasting black, purple or white blotch in the center.
Annual poppies grow best if they get a period of cold and wet. Plant them in fall, sprinkle them on late winter snow or plant them once the ground warms in May and keep them evenly moist for 10 days. Scatter the seeds on the ground, step on them to ensure good soil contact and do not cover them as sunlight is needed for germination. When the plants are about 3 inches tall, thin out any crowded clumps.
Poppy flowers are brief. While the stems sometimes produce two or three buds, most produce only one. The flower lasts only one to three days before its petals drop, not even one day if the weather is windy. Although the blooms are useless as cut flowers because of their short life, dried poppy seedheads are decorative and valued in flower arrangements.
Specific cultivars, such as Lauren's Grape (purple), Danish Flag (deep orange with white feathery centers) and peony poppies (multiple petals in jewel tones), yield just one type of flower; however, color mixes of rose, red and orange tones are available. Store-bought poppy seeds are cheaper and usually produce plants with a single pink bloom than those in nurseries.