I have allowed a monster into my garden. It's a beautiful monster, but still one to be reckoned with. It is tha Matilija poppy (Romneya coulteri), a native of California and Baja California from the coast ranges to the foothills. A 6 to 8 foot plant that consists of mostly unbranched stems covered with pointy gray-green leaves. At the top of each stem several huge white flowers open in sequence. Matilija poppy is nicknamed the "fried egg plant" (not the "fried eggplant"!) because the flowers and their yellow centers have the size and proportions of sunny side up eggs. I see why, however the flutter, crinkle, and translucency of the flowers seem to me to make them quite different and considerably more ornamental than the flat, opaque, platebound breakfast item.
The reason this plant can be a monster is that it will make a thicket of stems in a several square foot area, and it will send out rhizomes that will sprout suckers, sometime several feet from the parent plant. The good news is that the suckers are easy to pull or dig out, but the bad news is that the plant will make more. You can keep up with the suckers easily with weekly, or even biweekly care, but I wouldn't want to ignore a plant for several months.
Because I have found this fine monster to be manageable, in other gardens, I will give it a try. I will keep the suckers cut and cut back each stem after all of its blossoms have faded. Also, when, by about the third year, it has many stems, I will start cutting it to the ground when it begins to bloom less in autumn.