Tree fern (Dicksonia antarctica) - overwintering?

[Bob Carlile]

I purchased a tree fern this past spring and it is planted in a pot. It did quite well during the summer growing about 6-8 inches. This winter, should I move the pot indoors or leave in a covered terrace area? The terrace is protected overhead and enclosed on 3 sides, leaving only 1 side open to the elements. I live in Memphis, Tennessee, which I believe to be in zone 7b (5 to 10 F / -12.3 to

-14.9 C).

Thanks for any help, suggestions, or personal experiences.

[paghat]

I'm in Zone 8 and placed mine in a sheltered corridor right in the ground. Its first year it got some slight winter damage because we had a few days in the 20s. 20 degrees is supposed to be the low-end of safe tolerances & even that should not be extended. This year we've already had one unseasonably cold week in the 20s, that was about two weeks ago, & the tree fern showed no signs of injury from that week-long chill. In a protected spot I don't believe they need much winter assistance here on Puget Sound, which is milder than Tennessee. If it is ever announced that temperatures were going to fall into the teens (which happens once every four or six years & rarely lasts long), I would certainly go out & wrap the fern in newspapers or a blanket. Before spring, any winter-damaged fronds can be snipped off, they'll grow back rapidly enough.

At Heronswood near us, they have in their display garden some full-sized tree ferns. They've very sheltered under Douglas firs, but the owner feels they do need protection even here in Zone 8, so ghe ties up the fronds in a bundle & wrape the whole fern from top to bottom in burlap.

I compared a lot of reports on these ferns as grown in Vancouver B.C., Scotland, London, Seattle, & Portland Oregon. Some reported major damage & even death from winter exposures, but others have fully evergreen ferns even in exposed sites. The theory is that the ones that do well in chillier climates originated from strains initially obtained at higher altitudes & so much more cold-hardy than those from sea level, but to date no grower identifies a cold-hardy strain, so we have to experiment. I think in zone 8 the experiment has a high probability of success, but zone

7 will more likely require winter wrapping, since exposures below the 20 degrees F. are more certainly going to cause some damage, & below 15 degrees can kill it entirely.

In your zone, winter damage is more certain. Since mine's in the ground & yours is potted, yours will be even more at risk, because pots chill a plant much faster than being in the ground. But I can't hazard whether it would be safer indoors or not, because I suck at caring for plants indoors & only risk succulents to my indoor care. My sense is that it would be likely dry out indoors because average humidity ain't good for ferns. If you left it on the terrace but could move the pot right up next to the house (or especially next to a glass door) it would have residual warmth from the house, then wrap the trunk &amp pot during the coldest weeks or months -- I suspect it would be more easily overwintered that way than if you had it inside the house, but I'm just guessing on that score.

Here's mine:

the ratgirl

[hermine stover]

for ME these have always behaved like semi-tender greenhouse subjects and anything like prologed temps below fifties has NOT had a good effect on the plant. this is MY own experience, regardless of what the books say.

hermine