Just lights and mulch will not be enough. You definitely have to cover it with something to keep the heat from the lights in. I dont use high powered christmas lights for my palms and they dont seem to have a problem. This year I'm using very low powered lights that barely generate any heat at all so I am a little worried about the palms this year. I'm hoping for mild temperatures and we'll have to see!
But there is no reason why you cant get a Mule palm to thrive for you! There is a large 10 foot tall butia a few blocks away from me that is protected every winter and it looks great and is HUGE. Mule palms have a similar cold tolerance to Butias so I'd try them first and once you master that definitely give Mule palms a try.
Good luck!
-Alex

I would try to find older xmas lights. the new LED's do not get nearly as hot and I'm not to sure how they would work. the old large bulbs I think there called 9a or somthing like that work best.

Thank you Miketropic and tropicalzone7 for your replies. I have 1 question for both of you. Tropicalzone7, should I cover the leaves? Or is that unnecessary? And miketropic: What exactly are those christmas lights called? I can't find them online.

Miketropic, are these the ones you are talking about?

http://www.ebay.com/itm/LIGHTS-Christmas-Fairy-Mini-Flame-100Pc-RED-PINK-GREEN-BLUE-GOLD-NOS-2004-9A-/261100228784?pt=LH_DefaultDomain_0amp;hash=item3ccac950b0

C-9 and C-7 lights are what you want-are you saying it is possible to bring it inside?=is this in a pot?

No i am not bringing it inside. So I should get C-9 xmas lights?

Ok I will be getting these: http://www.amazon.com/Good-Tidings-Holiday-25-Lights-Multi-Colored/dp/B00466IGBY/ref=sr_1_fkmr1_1?ie=UTF8&qid=1357401352&sr=8-1-fkmr1&keywords=c-7+christmas+lights+non-led

Yeah the ones Jim put up are the good ones I knew they had a letter and a number to them.

I've found that even putting a blanket over the top with a spotlight shining underneath keeps it pretty warm in there if you need some short term protection from cold.

I would definitely cover the fronds. Moisture can sit in the center of the crown and when it's below freezing outside, that can help a palm rot and Mule palms generally start getting frond damage in the upper teens and a typical winter around our area gets several degrees below that.
Good luck!
-Alex

Thank you tropicalzone7! I think what I will do is wrap the palm in christmas lights then wrap burlap/bubble wrap around them all the way to the leaves. And then maybe throw a garbage bag over it. And I wouldn't forget the mulch at the base! Since my primary residence is in Manhattan and only come out to Hamptons only on the weekends. And since we may be purchasing a house in Palmas Del Mar, Puerto Rico, we might only come 2-3 weekends a month. So should I always keep the christmas lights on?

Do a google search for thermocube and use one of those. It will turn the lights on at 35 degrees or colder and off when temps hit 45. Definitely possible to keep one alive though.

Thank you! Just a question, can I connect it to an adapter?

Oh and would they power up christmas lights? Or only heat tapes?

I'm pretty sure a thermocube will power up any electrical device so christmas lights will be fine. And you can keep the christmas lights on the tree for as long as you want, but I definitely agree with Islandbreeze, get a thermocube so you dont actually have the christmas lights turned on all winter long. I use low powered christmas lights, but I still have had my palm enclosures reach 70F on 50F winter days and the problem is even worse during the end of winter when the sun is higher in the sky.
Good luck! And if you get a house in Puerto Rico, you will have the chance to plant a lot awesome tropical palms too!
-Alex

thank you tropicalzone 7!

Okay, I just had to get one--arrived last night. I like both Queens and Pindos, but what I appreciate about the Mule is both the very tropical foliage and the more restrained vertical growth. I know it will eventually get much taller but seems like it would take longer to do so--compared to Queens. Therefore, easier to protect. My Queens have to get dragged into the garage every season and already are hitting the ceiling.

How tall does the mule palm get? Does anyone know?

Mule palms get big, so big that you won't be able to protect it at some point. They get over 20 feet tall, taller than a mature pindo.

They grow relatively fast too, fortunately they dont get to huge sizes for many years, but they are definitely taller than most mature pindo palms and are probably the fastest cold tolerant pinnate palm (although what you consider a cold tolerant palm is relative)
-Alex

So do you guys think I HAVE to cover the fronds, even if I have xmas lights and burlap around the trunk? As well as mulch on the base? If I had to, I would wrap bubble wrap on top of the burlap!

If you want the palm to look nice in the spring then I would definitely cover the fronds. If you're just looking for survival then you dont have to cover the fronds but if a palm is only hanging on by a thread after winter then it will have a hard time recovering year after year.
-Alex

Yeah, I understand what you're saying, but is there away to protect the fronds without neccasarily covering them? I know it's a stupid question lol

No, it's definitely not a stupid question! If winds were calm all the time then you might not need to actually put much additional protection other than some lights , but since winter is often very windy it would never work. You dont have to protect Mule palm fronds for that long though!
During the average winter if you protect the fronds of your palm from mid December to late February, maybe the first week of March, then your good to go. They will only be covered 6-7 weeks of the year during the average winter and during winters like this one you wouldnt even need to protect it at all yet since we have not gone below 22F (not sure how cold it got in the hamptons but that's my lowest temperature so far in NYC). You really only have to protect the fronds below 20F and we have definitely not see temperatures like that too much the past 2 years!
-Alex

I want add DONOT use c-9 lights. Regular incandescent lights (the ones that come in string of 100) are hot enough. ONE string is enough to make the temperature in an insulated space reach over 100 degrees and damage the palm. If you don't like the look of protection and are willing to do extra work you can remove the protection during warm spells above freezing and put it back when temperatures are below freezing.

I think the best way to protect a large mule palm would be to wrap the tree in mini christmas lights with a thermo cube inside to regulate the temperature, then wrap the tree in burlap to prevent the leaves from touching the plastic. Then wrap in clear plastic(plastic drop clothes for painting are good or plastic wrap) finally mulch with a foot of mulch to protect the roots.

No, I'm fine with wrapping the trunk. You didn't mention me wrapping the leaves, in contrast to tropicalzone7's method who says it is a must. I wouldn't remove the protection throughout the winter because I don't mind the trunk wrapped. So I should use c-7 lights (non led) or the modern led's?

Zone 7... Brrrrrrrrrr.

Here is a photo of Spencer Mallets Mule palm Northern Texas.

Nice palm! How old is it and what zone is it in?

North Texas is mostly a zone 8, especially around the Dallas area where I'm guessing this is. You could probably get away with growing windmill palms in your area with out winter protection after a few winters or two for acclimation. Why not do that instead of laboring with trying to keep mule palms which (from what I've read) are not that cold tolerant? Queen palms in beach resort areas seem to be readily available, priced to move and often used as annual plantings...I would plant a few of those and a few windmills to get the best of both and just let the queen palms go at the end of the season.