Evening Primrose (Botanical name: Oenothera biennis) is a plant from Onagraceae famiy origionaly indigenous to North America, but is now found in Europe, Asia, New Zealand and Australia too. The beautiful yellow flowered is named Evening Primrose because the flower blossoms only at night. The plant is famous medically. It’s seeds, leaves, oil of the seeds and root are used in medicines. Night-time insects like nocturnal sphinx moth pollinate these plants. The plant grows between 3 and 5 feet tall. The flowers are between 0.78 to 2 inches.