Although Astra might have seemed completely insane and idiotic, blasting lightning with reckless abandon and setting off explosions of Boom corn, it was not in fact the case.
When Astra pulsed, she got signals back from everything with an electrical source, or other energy she could absorb, within it. Usually this would be things like street lamps, electrical generators or the literal sun, to name a few. It also included people, as they used electricity in their nervous systems.
But it also included plants. Although they did not have a nervous system, they still used an electrical current in their day to day lives of basking in sunlight. It was simply tiny compared to the other sources, so it was relegated to background noise.
