A Matilija poppy is a flowering perennial shrub, a member of the genus Romneya in the poppy family. There are two unique species of Matilija poppy that are both native to northern Mexico and southern California. The plants are popular garden plants because of their large, white flowers, which are acclaimed as the largest flowers found growing as part of California's native flora. In the wild, the shrubs are commonly found growing in dry canyon beds, amongst other drought-resistant shrubs.
Two unique species of the shrub are recognized; these are Romneya coulteri or Coulter's Matilija poppy and Romneya trichocalyx or bristly Matilija poppy. The species are very similar in appearance, and can only be distinguished from one another by studying their sepals, or secondary green, petal-like structures that protect the flower while it is still a bud. Bristly varieties have sepals that are covered in small, stiff hairs, while plants of the Coulter's variety have smooth sepals.
Matilija poppy plants typically grow to a height of about four to six feet (one to two meters), although the plants can grow as large as eight feet (about two and a half meters), given good growing conditions. They are bushy plants, with toothed bluish-green leaves. Their showy white flowers bloom between late spring and early fall. These flowers are broad and flat, with delicately creased white petals and round, brilliant yellow centers. Due to the fact that the white petals somewhat resemble egg whites and the large, round centers look similar to egg yolks, the flowers are sometimes called "fried egg flowers."
Plants may be propagated from seed or by root division. Root division is a kind of asexual plant reproduction that involves dividing a single root bundle into separate root structures and planting each root as a new plant. Like most poppy species, the Matilija poppy can be an abundant source of seed because its flowers dry on the plant into small pods full of seeds that can be easily harvested. However, most plants grown in gardens are usually purchased as seedlings and then transplanted.
The Matilija poppy prefers to grow in conditions of full sun, with moderately moist soil. However, the plant is also very tolerant of drought conditions. For the most part, the plants are very easy to grow and maintain, requiring infrequent watering and fertilization, and occasional pruning. They are so successful in some regions that some consider them to be an invasive weed.