Many plants have seasonal rhythms as well

Many plants have seasonal rhythms as well. As spring melts the winter frost, phytochromes sense the longer days and increasing light, and a currently unknown mechanism detects the temperature change. These systems pass the news throughout the plant and make it produce blooming flowers in preparation for the pollinators brought out by warmer weather. Circadian rhythms act as a link between a plant and its environment. These oscillations come from the plants themselves. Each one has a default rhythm. Even so, these clocks can adapt their oscillations to environmental changes and cues. On a planet that's in constant flux,
it's the circadian rhythms that enable a plant to stay true to its schedule and to keep its own time.