Dormancy is not physiologically required in Dionaea muscipula

If you've spent any time in the carnivorous plant community, you've almost certainly been told that Venus flytraps must go through winter dormancy or they'll eventually weaken and die. This claim gets repeated so often that it's treated as settled fact. But when you actually look for rigorous evidence supporting it, you come up short.

I want to be upfront about my own growing practice: the vast majority of my plants go through dormancy every year, and I've only recently begun experimenting with skipping it. I started with a single generic clone from Target about three years ago, specifically because I expected it to decline and didn't want to risk a valuable cultivar. It hasn't declined. That experience, combined with a careful look at the available evidence, has convinced me that the importance of dormancy is significantly overstated in this community. In this post, I'll walk through the evidence, share results from my own experiment, and use a bit of population biology to show that even under worst-case assumptions, skipping dormancy is a winning strategy for anyone looking to maximize growth.

The evidence against required dormancy

There are several independent lines of evidence suggesting that dormancy is not physiologically necessary for Venus flytraps.

The first comes from experienced indoor growers. John Brittnacher, former president of the International Carnivorous Plant Society, has grown Venus flytraps indoors without dormancy for over 20 years. In his ICPS care guide for Dionaea and in a more detailed article in Carnivorous Plant Newsletter, he is unequivocal:

"In spite of what many people believe, VFTs do not require a terrarium nor do they require dormancy to survive long term indoors. The plants only require dormancy if they are going to experience freezing temperatures outside. Putting an indoor plant in the refrigerator to encourage dormancy is a waste."

Brittnacher isn't alone in this experience. Matt Miller, owner of Flytrapstore.com and one of the most prominent Venus flytrap vendors in the country, has come around to a similar view:

"You've definitely opened my eyes (along with what I've seen John Brittnacher do over the years) to what Dionaea can withstand if they are constantly fed and provided good artificial lighting. Again, it is very much like what they do in tissue culture."

The second line of evidence comes from tissue culture itself, which represents one of the longest-running and most highly replicated experiments in dormancy-free cultivation. Commercial tissue culture labs grow and serially divide Venus flytrap cultures for thousands of sequential generations under constant LED lighting and stable environmental conditions. These plants do not experience dormancy of any kind. The cultures only need to be restarted when accumulated somatic mutations eventually cause developmental issues, which can take decades. If the absence of dormancy caused physiological decline, tissue culture operations would not be viable, yet they clearly are.

The third line of evidence comes from tropical growers. Many people successfully cultivate Venus flytraps outdoors in tropical climates, where seasonal changes in photoperiod and temperature are minimal. Growers near the equator report year-round active growth with no stalling or decline. This is admittedly the weakest of the three lines of evidence, since even modest variation in photoperiod could theoretically induce some degree of dormancy, but the consistent reports of uninterrupted growth are suggestive.

Three years without dormancy: my experience

I've now gone three full years without dormancy for a typical Venus flytrap clone purchased from Target. The common prediction is that plants will become "exhausted" without a rest period, but I have not seen any sign of this. Over those three years, this single clone has produced roughly 60 divisions.

To test the dormancy question more directly, I ran a small experiment. In September, I took a single plant with seven growth points and divided it. Two divisions were placed under dormancy conditions (9 hours of light, 50 to 60°F) from September through January, while five were kept under standard growth conditions (16 hours of light, 70 to 80°F) the entire time. In late January, I brought the two dormant divisions back under my normal growing conditions.

As of March, all seven divisions are doing well. The five that skipped dormancy are each the same size or larger than the parent clone was back in September when the entire pot was divided, and they show no signs of exhaustion whatsoever. Several are ready to divide again. The two that went through dormancy are healthy, but considerably smaller. In practical terms, skipping dormancy gave me an entire extra generation of asexual growth: while the dormant pair sat idle for three months, the non-dormant clones were actively growing and are now significantly further along in their development.

The math: why skipping dormancy wins even in the worst case

Let me take this a step further with some quantitative reasoning. Even if we grant the strongest possible version of the "old plants need dormancy" argument, the math of population biology still favors skipping dormancy, at least for anyone whose goal is to grow more plants.

Biological populations grow exponentially by default: as organisms reproduce, their offspring reproduce in turn, and the population compounds. A key consequence of exponential growth is that the age distribution stabilizes very quickly into a geometric distribution, where young individuals massively outnumber old ones. If each plant produces five divisions per year, then by year three the population is roughly 83% age-zero plants, 14% age-one, 2% age-two, and less than half a percent age-three or older. The original founder represents a vanishingly small fraction of the total.

This holds even at much slower growth rates. At just two divisions per year, only about 4% of the population is three or more years old. The faster the growth, the younger the population skews.

Steel-manning the dormancy cost: let's assume every plant that skips dormancy dies after 2 years. What then?

Let's assume the absolute worst-case scenario: lack of dormancy causes 100% mortality at age 3. Every single plant that hits its third birthday just keels over. Brutal, right? Surely then inducing dormancy would be better than skipping it?

But here's the trade-off: dormancy costs you roughly 3 months of growing time per year, assuming you are an indoor grower with access to lights. If you get 5 divisions per year without dormancy, you should only get about 3.75 with it.

So which strategy wins? We can solve for the population growth rate (λ) using the Euler-Lotka equation, which is the fundamental equation for finding the growth rate of an age-structured population. The general form is:

With dormancy (infinite lifespan): Every individual survives forever (l_a = 1 for all a) and produces r = 3.75 offspring per year. The infinite sum simplifies to:

This is the familiar result that for immortal populations, the growth factor is just one plus the per-capita birth rate.

Without dormancy (death at age 3): Individuals produce r = 5 offspring per year but die when they hit age 3. The sum truncates to just three terms:

Since 5.98 > 4.75, the no-dormancy strategy wins. The population grows about 26% faster per year, and that advantage compounds:

Starting from a single plant, after 10 years:

• With dormancy: ~5.8 million plants
• Without dormancy: ~58 million plants

That's nearly 10× more plants over a decade by skipping dormancy, even though every single one of them dies young. The extra growing time, and the compounding power of exponential growth, more than compensates for the (hypothetical) lifespan penalty.

The takeaway: even if we grant the strongest possible version of the "old plants need dormancy" hypothesis, it still doesn't matter. The math favors skipping dormancy as long as you're getting that extra growing time. And remember, there's no actual evidence that old non-dormant plants die, so this is a worst-case scenario that almost certainly overestimates any real penalty.

Addressing other counterarguments

The most common objection is some version of "I skipped dormancy once and my plant did poorly the next year." I don't doubt these experiences, but without a controlled experiment that varies dormancy while holding all other conditions constant, there's no way to attribute the outcome to dormancy specifically. Indoor growing conditions vary in countless ways, from light quality and duration to watering and temperature, and any of these could be responsible. This is a textbook case of confirmation bias: you expected dormancy to matter, so when something went wrong, you attributed it to the most salient variable.

Another frequent response is that dormancy is part of the plant's natural cycle, so of course it must be necessary. Venus flytraps do go dormant in their native habitat in the Carolinas, but they do so because they need to survive freezing winters. Dormancy is a survival mechanism for cold, not an intrinsic physiological requirement for health. Many plants have environmentally inducible developmental programs that they can skip indefinitely without consequence. Some annuals, for instance, can be kept growing for years if the photoperiod never triggers flowering. The existence of a developmental program doesn't mean the organism requires it.

A subtler objection is the claim that plants growing indoors, in tissue culture, or in the tropics might be experiencing some kind of "cryptic dormancy" that isn't externally visible. This is a textbook example of moving the goalposts. Tissue culture plants in particular are grown under constant conditions optimized for maximal growth. Any individual that slowed down would simply be outcompeted by those that kept dividing, and would no longer be an ancestor of future generations. The idea that these plants are secretly resting is not supported by how tissue culture actually works.

What I'm not saying

I want to be clear about what I am and am not arguing. I am not saying that dormancy is never useful. If your plants are going to experience freezing temperatures, they absolutely need to be dormant or they will die. I can also imagine that certain combinations of environmental signals, like warm temperatures paired with very short photoperiods, might cause real problems by sending conflicting developmental cues. That would be an interesting hypothesis to test.

I'm also not telling anyone how to grow their plants. There are plenty of good reasons to put your flytraps through dormancy. Maybe you like the way plants look after a dormancy period. Maybe you want a break from caring for them over the winter. Maybe you don't have room indoors for thousands of plants, or don't want to spend the money on lights and electricity. Maybe you want to synchronize flowering time to do crosses. Maybe you just want to provide them with a more natural life cycle. All of these are perfectly valid reasons.

My argument is simply that we should stop telling new growers that dormancy is an absolute requirement for plant health, because the evidence does not support that claim. In particular, advising someone to use the refrigerator method (which is arguably the worst common approach to inducing dormancy) because "otherwise your plant will die" is, in my view, bad advice. A better recommendation for an indoor grower would be to invest in a good grow light and enjoy vigorous, actively growing plants all winter long.

The bottom line

We have multiple independent lines of evidence, from experienced indoor growers, from decades of commercial tissue culture, and from tropical cultivation, showing that Venus flytraps can thrive indefinitely without dormancy. My own three-year experiment with a generic clone has produced dozens of healthy divisions with no sign of decline. And even under the most pessimistic assumptions about what skipping dormancy might do to older plants, the population-level math still overwhelmingly favors continuous growth.

The carnivorous plant community has a lot of received wisdom that deserves a closer look. I think the dogma around dormancy is one of the clearest cases where the conventional advice doesn't hold up to scrutiny. If you have evidence to the contrary, especially from controlled experiments, I'd genuinely love to see it. But until that evidence materializes, I'll keep my lights on year-round.