Venus flytraps go dormant because they are temperate perennials. All perennials die back in winter and grow back in spring. But, WHY? Because it’s energetically expensive to NOT go dormant over winter (when they’re outdoors) because:
- They get so much less sunlight/energy over the winter they would have serious trouble supporting themselves.
- It’s harder to transport water through the roots when temperatures are so cold and water may be freezing or near-freezing
- There are almost no bugs in winter to supplement a Venus Fly Traps nutrient-poor growing medium.
To survive the winter, Venus flytraps have evolved to go dormant. If they didn’t go dormant, venus flytraps would probably be extinct. Since their biology dictates that they are perennials, they can’t survive for more than 2 or 3 years without dormancy. It would be analogous to a human who never ever sleeps.
If Venus flytraps’ natural habitat were tropical, they’d have evolved to have a very active growing season in the summer and a slightly less active growing season in winter, like the tropical pitcher plant Nepenthes.