We are pretty happy ourselves that their bloom times overlap.
Matilija Poppies can grow to eight feet high and will spread through underground runners where conditions are suitable. Huge swathes of them cover hillsides in Southern California, where it can become invasive in light, sandy soils. Here in the Pacific Northwest, with our clay soils, they are harder to establish, and tend to behave themselves a little better than their warm-climate cousins.
Here's another flower, on a stem that has flopped into a nearby Caryopteris x clandonensis 'Worcester Gold,' which is just starting to show its lovely blue flowers.
Romneyas tend to go dormant after flowering, usually dropping all their foliage, and you might be tempted to think it has croaked. More likely than not, it is just resting and will emerge healthy and robust the following spring.
Unless it dies, of course.