I can't help you with the species...sorry. Is that snow in the last photo? If so I would think that was the problem. As far as I know tree ferns here do not grow where it snows in Aust. They like it much warmer, some will take some sun, but most grow better with some shade...unless you have a mild summer. Wind will damage the fronds, they also need a bit of water through summer, at least every other day if it is hot and breezy. Some folk in the warmer areas here use a cool drink bottle with a small hole in the lid. Fill up the bottle and upend it in the crown. No advice for snow...sorry.

I would continue to watch it for a week or so. There are two basic possibilities: damage to the central bud or damage to the roots. I'm guessing it's root failure based on the appearance of those droopy emerging croziers -- a classic symptom. It could be due to compacted soil, drought, pH problems or contact with weed killer. A tree fern planted that close to a home foundation is going to have a lot of lime leached into the root system. I would plant it out away from the house in a soil heavily enriched with compost and generously mulched. FWIW, in the future don't remove old fronds before the replacement fronds have unfurled. It takes a lot of energy for the plant to pump out new fronds and that energy has to come from somewhere. Ideally, it will come from photosynthesis from the old fronds. If the old fronds have died and are unable to photosynthesize, the fern may still be able to absorb some nutrients from the dying fronds to form some new (though probably stunted) new fronds. If the fronds are entirely removed, then there is no energy input for the fern to unfurl the new fronds forming in the bud. It isn't likely that this is the reason for the plants' failure, but it's something to keep in mind for the future. Ugly as they may be, dying fronds should remain until at least three new croziers have unfurled. I think the hummingbird issue is unrelated to the health of the tree ferns. I would also remove the Spanish Moss and put it on a tree or something. It looks unnatural on the tree ferns and spoils their natural beauty.

Sounds like the fern is not getting enough water. Be sure to water the entire trunk of the fern everyday. Keep in mind the trunk is actually a collection of roots that grow upward pushing the leaves taller. Freezing could have done some permanent damage. Try the watering and see if it recovers.

Australian tree ferns: Plant possible invasive concern by Carolyn Lucas West Hawaii Today clucas@westhawaiitoday.com Wednesday, March 18, 2009 9:07 AM HST Though prized for its distinctive looks and rapid growth, the Australian tree fern is becoming an increasingly common and alarming fixture in Kona neighborhoods, according to a recent islandwide survey by the Big Island Invasive Species Committee's early detection crew. On the underside of its triangular fronds with lacy blades are millions of spores, which breezes -- as well as feral ungulates -- carry far and wide. This tree fern (Spahaeropteris or Cyathea cooperi) is already displacing native forests on Kauai, Maui and Oahu. Watersheds are also being choked. Such propagation is just beginning on the Big Island, said Page Else, spokeswoman for the Big Island Invasive Species Committee. "The tree fern crowds out our native hapuu, the mother of the forest. The soft fibers of the hapuu nurture young native seedlings of native plants like ohia and olapa," she said. "The Australian tree fern has a harder, scaled trunk which doesn't make a good home for seedlings. Consequently, the foreign plant can take over in our forests, changing the forest structure, lessening the number of native plants and decreasing the ability to capture water and provide good water quality in watersheds." It's no wonder that the Australian tree fern appears on a list of the most invasive plants in Hawaii, prepared by the Hawaii State Alien Species Coordinator and the Department of Land and Natural Resources' Division of Forestry and Wildlife. Officials urged people to not cultivate any of the listed species anywhere in Hawaii. The Big Island Invasive Species Committee recently issued an Australian tree fern alert, spreading awareness about the weed and hoping that residents will help prevent its spread. People should report tree ferns by calling the state pest hotline at 643-7378. Those who have purchased the popular ornamental but suffered buyer's remorse and now want to remove it can either snip the bud or cut down the tree fern and treat it with herbicide. "They should be aware that their tax dollars will be put to work combating the rapid growth of this plant in public watersheds as seeds spread out of their yard into other locations," Else said. Two years ago, the Kauai Watershed Alliance contracted the Nature Conservancy to coordinate a response to the invasive tree fern. Crews on foot are sent into valley uplands to remove plants at a cost of $365 per acre. Helicopters with herbicides spray in more remote, dangerous areas. The aerial spraying costs $560 per acre, Else said. James Leary, invasive weed specialist at University of Hawaii at Manoa College of Tropical College Agriculture and Human Resources, has been experimenting with an innovative way to apply herbicide selectively to Australian tree ferns by using paintball guns with a special pesticide formulation. While people may be fond of the tree ferns, a wide variety of noninvasive alternatives, including the native hapuu, can be used as ornamentals. Because each yard is different, residents can visit a nursery and talk to an expert to find the best fit. Many nurseries -- including 15 on the Big Island -- agreed not to sell the tree fern after learning its potentially detrimental impact. For more information, call the Big Island Invasive Species Committee at 933-3345.