Matilija poppy plants are native to California and are, therefore, a good choice if you’re looking for a local flower that can weather a drought or two. That being said, Matilija poppies are far from a sure thing in the garden. They are famous for being both hard to grow and invasive, and care of Matilija poppies can be tricky to figure out at first.
Even though this is a drought-tolerant perennial, water it thoroughly after planting and continue watering weekly throughout the first growing season. Once this poppy is established, you may not need to water it ever again. Matilija poppy commonly goes dormant in the heat of summer or in fall. Water your new plant at least once per week while it's getting established. Matilija poppy plants spread by rhizomes, so bury some sheets of metal around the plant to help contain its takeover of your garden.
Grow in well-drained, moderately fertile soil in a sheltered, sunny site. Protect in winter in cold areas.
Temperatures between 65 (18 °C) to 75 F (23 °C) and nighttime temperatures between 50 t(10°C) to 60 F (15 °C).