Q/A #5 - Did a Sudden Freeze Kill My Flytrap and Sarracenia?

QUESTION:
I tried to be brave and keep my plants outside, but I'm honestly afraid the cold has killed them. I'm growing two Venus Flytraps and a Sarracenia purpurea. I'm in zone 6 and we haven't yet had snow, but the overnight temps drop below 20°F (-7°C). When I check on the plants in the morning, their (distilled) water basin and soil is completely frozen. What should I have done differently? Should I toss these poor babies in the trash and start over in the spring? For reference, the plants live by our front door on the porch where they get full sunlight all day. They are facing south. The plants have never been repotted since they were shipped to us.
(Submitted in December 2020.)

RESPONSE BY JEFF DALLAS:
Your Venus Flytraps may have bit the dust. It's hard to tell just from the leaves alone since the bulb may be alive still. Trim all the dead stuff off, and take a look at the bulb beneath the soil. If it's still nice and white, the plant(s) are still alive. If they are brown, or have streaks of brown going through them, say some final words. Even though they can withstand a freeze, a sudden drop in temperature and being exposed like that can kill them.

Now some good news. Your Sarracenia purpurea is fine. They are pretty tough, and it looks exactly as it should for this time of year. I see about three nice looking pitchers, so that lets me know the rhizome is still alive. The rest have some browning, which is normal at this time of the year. Pitchers from early in the growing season tend to die off in the Fall. Just trim any brown pitchers off when you can't stand looking at them.

I would also move your plants to a cool window in the house for the winter. Keep the pots next to the window pane and make sure the soil is always moist. Spray them with a sulfur fungicide to prevent mold on the soil. Next spring you can move them back outside. It would be good to transplant them into larger pots at that time. You can even put all three (if the Flytraps are still alive) into a single large pot. The large pot will temper temperature swings and better protect your plants.

Flytraps and Sarracenia are completely capable of handling a zone 6 winter, but they have to be properly set up to do that. Most plants that are normally considered hardy, even some native perennials you may have in your area, would probably die if they were potted in 3" pots, and left exposed on a porch or up on a table or bench. In other words, this isn't really about carnivorous plants being any more or less hardy than other plants, it's more of basic gardening stuff. Plants in pots are often considered to be one or two zones less hardy than something that is in the ground or in a large planter. What usually happens in small pots is they dry out and dessicate during cold. We've had Venus flytraps survive temperatures as low as 7°F (-14°C) in our nursery, but that's well covered up, with pots in pools on the ground. This protects them from freezing wind, which can be very damaging to all types of potted plants.

• Submitted in December 2020. The original question and response have been edited for publication.
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