looks like the plant was either too dry at one point or some roots were damaged.
I'd wait until new growth resumes and than remove the damaged foliage.
Make sure to keep it moist but not saturated until it starts growing again.

dp

It's midwinter. Cold, dark, short daylengths. Cyathea cooperi is a Queensland sub-tropical tree fern that just wants to keep growing - except we seldom have the resources to make that possible in our winter climate. This fern is stalled, in effect, and is stressed. The last thing it needs is drastic over-potting, as in the picture, and soaking! You'll lose even more fronds. My advice is to more accurately simulate the parameters that trigger growth - high light for photosynthesis, long daylight period, sufficiently high temperatures for metabolizing nutrient, high atmospheric humidity, etc. My guess is you're not giving it enough light relative to the high indoor indoor temperatures you're keeping it in.

Sickly midwinter ferns never benefit from piling on more compost, fertilizer and water. And winter is a bad time to acquire them.

Steve - Brighton, Sussex, UK

A few more thoughts...

'Spraying'. Unfortunately, not the same thing as high humidity. If your indoor growing conditions are hostile - and 99.999 per cent of windowsills are - occasional spraying will make no difference at all. Buy yourself a cheap hygrometer - a few dollars from any pet shop that sells reptiles and frogs - calibrate it properly, and then check how depressing life is for humidity-dependent plants like baby tree ferns in our centrally-heated homes. Cyathea cooperi loves to be around 70 - 80 per cent RH, yet a centrally-heated home in cold and dry February might typically score about 30 per cent. And what difference will a bit of spraying make? Well, you'd need misters running 24/7 to crank up the humidity to comfortable tree fern levels and that would be unbearable for you and yours. Your wallpaper will sprout fungi, the furniture will rot, and your family will contract exotic respiratory diseases.

And as for sickly tree ferns 'recovering'... Once a frond has sagged and gone dry and crispy, as in the photos - that's it. They can't come back. You might see new croziers appearing to replace them - usually smaller and weaker than before - but damaged fronds are always beyond recovery. That's tree ferns, I'm afraid.

This FAQ is a regular on Gardenweb forums, but the conclusion is always the same. Don't expect tree ferns of any hue to survive for long as houseplants. If your outdoor climate is too harsh for overwintering tree ferns, a heated glasshouse or humid conservatory is virtually essential.

One last thought. If it's possible to buy those cheap PVC zip-up mini greenhouse contraptions in the US - they're very common here in the UK for protecting seedlings - then you could rig one up as a kind of indoor 'intensive care' unit for your baby Cyathea. I use them all year round for my tree fern propagation programme as they maintain reasonable humidity in otherwise hostile indoor situatons. They are a kind of terrarium enclosure, I suppose. The modifications I make involve taking out all the shelves and bracing bars, hanging two aquarium light fixtures inside across the top, and standing the whole contraption inside a plastic greenhouse tray lined with wet capillary matting. Plenty of head-height for fast-developing fronds. Without very much daily effort I can simulate something close to humid sub-tropical conditions and my tree fern 'seedlings' grow very fast. As a one-season-only remedy for your dying Cyathea cooperi - it will outgrow this set-up by winter 2006 - I'm pretty sure this will work. But as for NEXT year....?

Steve - Brighton, UK

Thank you for your response. I put that fern in the middle of the floor to take a picture of it. I have it placed right beside the window otherwise.

I bought these ferns because they are cold-hardy. According to online sources, it can take 10° F (-12° C). For the two months, it's been cloudy and rainy here, not the normal weather pattern. Perhaps one or two days a week of sun.

I meant to plant it outside in a couple of months. I wonder what would happen if I planted it (and the dicksonia antarctica I bought at the same time) outside and used cold-protection strategies when needed? i.e., wrapping burlap and then plastic around the plant at night.

Your comments would be appreciated. Thank you.

that is stretching the cold hardiness of cooperi by about 20 degrees.

In most cases a 30 degree night will either kill or main that Cyathea.

Cyathea cooperi is a subtropical tree fern, capable of living through a short-lived frost in the high 20's, nothing more. A FEW species of tree fern are temperate plants, but NOT cold temperate. If you attempt outdoor culture in your area with anything less than a sealed greenhouse for the winter months, your plant will go into decline very quickly indeed. As for the Dicksonia, it is capable of sustaining cold snaps (lasting a day or two) down into the middle teens, but even then mortality is uncertain. Better to keep it above 20F (even then it will lose its fronds). However, this plant is NOT reliably heat tolerant in the summer months, disliking sustained temps above the mid 80's.

Tree ferns are not cold tolerant plants, and that includes the Dicksonias. A number of species grow in the cool temperate climates of Australia and New Zealand (the ones you commonly see offered as "cold hardy" by "online sources"), high in the mountains of Papua New Guinea (experience frosts), in South Africa, and also in the mountains of Central and South America. Rather than being cold hardy plants, these are ecologically highly specialized plants that require moisture levels consistent with rainforest conditions, protection from high winds (as in a well developed forest), and a largely frost free environment (yes, some do grow in areas that get frost).

In the USA outside culture can only be recommended in zones 9b and above (8b and 9a a serious stretch) provided the species chosen can handle summer time temps as well. None will endure consistent, below freezing weather or any freezing of the soil their growing in.

Steve Pope, a common visitor to this forum, has tried a number of species in his relatively benign climate of coastal southern England (equivalent USDA zone 9). His attempts there speak volumes about the "cold hardiness" theory that has gained so much favor in the online world. To wit, not many have made it. Care to comment Steve?

PF

In theory, you can grow anything anywhere - NASA's undersea and space horticulture experiments demonstrate that - but the question is whether it's worth the effort. Only by drastic manipulation of your micro-climate is it possible to keep sub-tropical tree ferns in hostile climatic zones, and that means artificially maintained growrooms, humidified conservatories and frost-free greenhouses. In really unsuitable climatic zones - ie, most of the North American continent - standard garden overwintering techniques are insufficient. And yet, for the reasons expounded in the previous posts, tree ferns can't simply be shunted indoors to join you and the houseplants.

Many newcomers to the tree fern cult are mislead by all the 'cold-hardiness' hype surrounding what should, in gardening terms, really be considered an extreme sport. And those 'online sources' - yes, I know exactly who you mean - probably now ought to consider removing those flakey upbeat first-generation websites and start again. The early boosterism helped gain a wider audience for the tree fern hobby - I don't dispute that - but something of a monster has been created in the process whereby unrealistic enthusiasms are fed by a cynical garden industry. Alas, internet forums have also played their part in pumping up this unsustainable phenomenon.

There ARE NO cold hardy tree ferns anywhere on the planet! Just a handul of species that can, if all other conditions are met (and that's a big if), just about withstand the temporary overnight winter minimums encountered in the warm-temperate climate zones. And Cyathea cooperi, the most widely available species in the US, probably doesn't even warrant a mention in this category - it's best tried as an irrigated and mollycoddled exotic in more Mediterranean style gardens, such as in southern California and southern Florida.

An insulated and wrapped-up Dicksonia antarctica is your best bet in terms of getting through, say, a Zone 8/9 winter, but many US gardeners will be unable to provide cool and damp enough summer conditions. That's the Catch-22 part of the tree fern conundrum: the allegedly 'tougher' species will not appreciate your summers; yet the sub-tropical varieties usually can't survive the US winter, indoors or out.

So, select your tree varieties with care to begin with and be prepared for serious thought as to the lengths you might have to go in order to ammeliorate both winter AND summer extremes. And, maybe, don't even buy tree ferns at all if you are in a Zone8 or worse area.

Steve - Brighton, UK

My huband recently bought me one for my birthday and it was doing okay untill three days ago. I looks terrible. I was told as long as we didn't let it go thru a technical freeze it'd be allright but as I have been reserching it's untimely demise I am realising I should have brought it in a week ago or so. It's brown, it's droopy.....it looks so sad. I love this plant very much does anyone know what I can do to save it?

If you keep your plant in a bright but shaded area, it should pull out of it. I thought mine was dead but I kept watering it and now it's putting out two new croziers and appears to have adapted. If you put your plant on top of a saucer filled with small pebbles and water, evaporation will create more humidity. Good luck.

I'd have to say your best bet for trying to grow a tree fern in OK is the Dicksonia antarctica. Here's why; It's small enough to be dragged into a garage during the coldest time in winter. You might want to put a grow light overhead to keep it warm etc. During the summer you can dig a hole next to the foundation of your house on the NE side and the A/C from your house bleeds over into the surrounding soil. Here in Houston we go 120 days each year when it never gets below 78F, every afternoon in the 90s. Mine's growing ok planted in the soil.