Cameron,
If you're in Halifax proper (i.e. the pennisula) then you're actually in a zone 6b. I lived in Halifax for about 5 years and there are a few things to note about climate and the plants you've listed. Now, I'm not going to tell you that you can't grow the palms/plants listed, but I am going to make some suggestions:
Rhapidophyllum hystrix: The lack of summer heat will make growing needle palm more difficult. It won't be like Niagara or the Okanogan where the palm will be fine once established. It will need protection every year.
Sabal minor: As above. But the lack of heat will mean that any damage will take a long time to recover.
Trachy takil: The true species is completely untested... It's been suggested that it is most similar to 'Maniupr' and therefore likely a zone 8 palm. Don't be discourged though since I am going to be trying it in zone 5a!
Other Trachys: Probably your best bets since they grow well without heat.
Other palms: Most are far too tender, Sabal palmetto would be the most interesting from my perspective, but it would be painfully slow. You might add Jubaea to that list. Coming from a more moderate climate it would be a good fit. Again, serious protection would be needed. A lot fo the palms you list are fast growing and tall. They would very quickly get out of hand. Just a heads up look for slower growing/lower growing species which will last longer in the garden. Not trying to discourage you here, just trying to steer you away from disappointment. I think that Cycas panzuihensis (spelling) would be a good one to try with some minor winter protection!
You can get some of the better palms at a nursery in the valley, unfortunately the name escapes me currently. They also have Southern magnolia, Magnolia virginiana, Arucaria, etc... Ever seen the pics of the Monkey puzzle and So. mag in the Yarmouth area (USDA 7a/b)? Pretty impressive, but the So. mag almost doesn't bloom due to lack of heat!
Bamboo: MOSO? Seriously? Check out needmore bamboo for someone with a similar climate (warmer summers, shorter freezes) to see sme better options. I'd try rubromarginata and atrovaginata for the thicker culms you crave. If you really MUST have a timber, there are better options. I know that P. nigra and forms have all failed for a friend of mine in the northend. Don't trust the low temperature data given on bambooworld.com, especially in our long lasting cold the plants will be damaged at much warmer temperature then listed (i.e. near total top-kill of my P.nuda at -24C; total top kill of P. aureosulcata at -24C... Maybe have been more to do with frozen soil then anythng else, though). I'd try the following: aureosulcata and vars, bissettii, rubro, nuda, atrovaginata, fargesia (there are some at Pepperell and Vernon downtown that have been there for c. 5+ years).
Bananas: I know of at least 2 people who have sucessfully overwintered basjoo rhizomes in Halifax. The least work was simplay filling a pot with leaves then flipping it over on the pseudostem... It survived but only grew to about 2 feet with heavy fertilization (the lack of high heat is a killer there). I don't now of anyone who has tried to overwinter other species. FYI I lost an Ensete glaucum over the winter of 2003.
Broadway is your best bet for a selection of smaller hardy palms (I guess that would now be rice road greenhouses since Broadway closed). Tropic.ca is OK but the plants are small of not of top quality. For cacti you can ask me and I'll probably have it, and I can share cuttings. Otherwise beaver creek has plants of the highest quality, easily the best mail order nursery in the country. If you want ball type cacti they are the place to get them.
Hope this helps. Send me a PM and I can hook you up with cacti, palms, etc. from my personal collection.
Cheers,
Paul (USDA zone 5a, near Kingston, ON)
Here are a 'few' photo links:
Fall 2008 pics:
http://good-times.webshots.com/album/56 ... good-times
August 2008 pics:
http://good-times.webshots.com/album/56 ... good-times
Spring 2008, mostly Cacti:
http://good-times.webshots.com/album/56 ... good-times
A few more spring 2008:
http://home-and-garden.webshots.com/alb ... and-garden
Nova Scotia zone maps (USDA, 2 maps, average of the 2 is probably closer to the real values!):
http://home-and-garden.webshots.com/alb ... and-garden
And finally, my beaver creek order from this past April:
http://home-and-garden.webshots.com/alb ... and-garden
