Sorry, but definitely not. Coconut palms are very tender palms and they will be dead, probably before the first frost! People have a really hard time with them in California (to a point where they are rarely seen outside greenhouses and never fruit outside of a greenhouse) even in parts of California that dont go below 30f. The only place where they can be grown in the US is Hawaii, and Central and Southern Florida. Coconut palms will need frost protection in Central Florida during bad winters, so really Southern Florida and Hawaii is the only safe place to grow them in the 50 states.

If you want to try palms, your only option would be cold hardy palms. Those are sabal minors, needle palms, and windmill palms. Those will still need protection in MI, but they can handle temperatues down to about 10F (needle palms and sabal minors can handle 0F or less when older!) so those are your best bets. You can grow coconut palms in pots, but it will never fruit in a pot.

As far as tropical fruit in Michican goes.... I have heard some people getting papayas to fruit in northern climates (in the ground for the summer and dug up and planted in a pot for a winter indoors). I doubt the growing season is long enough for fruit to ripen, but with the new dwarf varieties, it could be possible! You can definitely grow some grafted lemons, limes, oranges, grapefruit, and other citrus in pots. The only citrus that will survive in Michigan is the Hardy Orange. Its not really a citrus, but very very closely related. It loses its leaves in the fall (unlike other citus) and the thorns on them are very very sharp (GREAT for large windows to keep people out!). The fruit is very interesting to look at and with lots and lots and lots and lots of sugar, its a little edbile!

Good luck!
-Alex

Also, I just wanted to point out that you are not in a zone 8b if you live in Michigan. The warmest zone in Michigan is a zone 6b. You cant determine your USDA zone based on just one winters lowest temperature. You have to base it on the average lowest winter temperature for many winters. In 2001, New York City had a winter that did not go below 20F, but I still cant grow zone 9a plants because I dont live in a zone 9a, I live in a zone 7a. Even during that winter, plants that were suited for a zone 9a would not have survived because it is the consistent cold and consitent moisture that also play a big part in what can survive and what cant.

Where in Michgan are you located? That may help with your USDA zone. If your in southern michigan by the lakes, you are probably a zone 6a/6b. If your are further north and inland, you can be a zone 5 or less if you are really far north in the state.

An example of a zone 8b would be Cape Hatteras, NC, Panama City, FL (maybe more of a zone 9a), Macon, GA, Baton Rouge, LA (maybe more of a zone 8a), and other southern cities like that. They have very comfortable winters and it is so mild in these places that people get extremely excited (to the point where all schools and businesses are closed) at the sight of a snowflake!

-Alex

Alex is absolutely correct. In your zone (4, 5 or 6) I'm not even sure that you could grow a cold hardy palm.

As for tropical fruit I find that papayas (you want a hermaphroditic variety) and some grafted mangos and citrus do quite well in containers with winter protection. Mine are kept in a greenhouse during the colder months. Not sure how well the papaya and mango would do inside a house but citrus are pretty forgiving. Even if they don't hold fruit the blooms smell wonderful.

i know i'm not zone 8b, but the winter was much milder than most. all the other winters i remembered were zone 6b tempreture(0 to -5f), but this year was 20 degrees warmer(zone 8b), and the coldest it got was around 10 degrees. i expect this is probably climate change because the average temretures were the same in other cities in michigan, and i think this is a result of global warming or climate change(maby shift of the ocean-air currents. but something is really wierd here. there was snow on the ground till may and then it snowed again in the middle of may. i think air currents air the cause).

Here is a link that might be useful: troy average winter tempetures

There's no way that Michigan is anywhere near a zone 8. I'm in MD and the warmest zone is 7b.

Major Cities in Michigan:

Alpena - USDA Zone 5a
Ann Arbor - USDA Zone 6a
Clinton Township - USDA Zone 5b
Dearborn - USDA Zone 6b
Detroit - USDA Zone 6b
Flint - USDA Zone 5b
Grand Rapids - USDA Zone 5b
Kalamazoo - USDA Zone 6a
Lansing - USDA Zone 5a
Livonia - USDA Zone 6a
Marquette - USDA Zone 5b
Sault Ste Marie - USDA Zone 4b
Southfield - USDA Zone 6a
Sterling Heights - USDA Zone 6b
Warren - USDA Zone 6b
Westland - USDA Zone 6a

Troy, MI 48085
Frost Dates
Vegetable Planting Guide
Fall 2011
Vegetable Planting Guide
Spring 2011
Frost Dates > Troy, MI 48085 Change Location USDA Hardiness Zone: 5B

Last Frost Date (Spring 2011): 5/15

First Frost Date (Fall 2011): 10/3

Average Growing Season: >149 days

I checked Troy MI low temperatures for this past winter and it did get down to 3F which is mild for Michigan, but still barely a zone 7a. 3F is a very doable temperature for overwintering cold hardy palms (needles probably wouldnt even need protection when established at a temperature like that), but it was a mild winter so you would need protection otherwise. However, you were right that this winter was near 20F above the usual winter since usually you are about -10F for the coldest night of the year (on average, but lately winters have been mlder for many in northern states). But you will get cold winters again. Dont believe in Global Warming because Florida had its 2nd worse freeze in at least 20 years this past winter (the worst freeze was the winter before this one where it was so cold that iguanas fell off the trees in Miami because their blood got to near freezing temperatures).

Climate Change isnt a new thing since that is constantly happening. Nothing on Earth is a constant. There was a time millions of years ago when there just wasnt any permenant ice at all on Earth (even on the poles). The tropics probably extended 40N and 40S in latitude, maybe more! But then before that there was a time when the entire earth from the equator to the poles was all covered in ice (before complex life existed). All the oceans were frozen over!
So basically the point of all that climate talk is that even nowadays, its not unusual for there to be warmer periods and colder periods. Right now we are in a warmer period, but its a 100% guarantee that it will get colder than average at some point in the near future, only to get back and above normal again.

I dont want to keep you from experimenting with plants since thats exactly what I do with my zone, however, growing tropical palms outdoors year round without an amazing greenhouse really is impossible. There is so much that they require other than just above freezing temperatures.

-Alex

Just to confirm, we never see them in California, I mean never. I have only seen them in Hawaii. I would grow one if I could, instead a have an ugly Mexican palm, some else planted. And I zone 10, we to never go down to 30, 32 was a huge nightmare, when half my plants died, but it only happened once.

The closest California can get to a coconut palm is a kentia palm and although tis a common palm indoors around the country, It will not be tolerant enough to survive severe frosts. It would be toast in November in Michigan and Coconut palms probably would be in decline before the first frost in michigan because its just too cool in the Fall.
-Alex

I live in the Downriver Detroit area of Michigan and grow a few hardy palms in a micro climate on the east side of my brick home. Stick with the Hardy palms like Sabal minor and the needle palm, although I do have a Sabal palmetto that has done ok. My palms are all shrubs even though some are trunk forming. I'm sure the cold stunts there size because of the short growing season and I just throw garbage cans over the top of them for protection. I always get some leaf damage every winter, even during our record warm winter of 2011.
If you want to see some great ways to over winter palms. Go to You Tube and check out the way some of the people in Montreal, Canada do it. They have some Windmill Palms that are 10 to 12 feet tall growing there and our zones are similar.