Is decorative molding Ok to install over existing lap/Hardiplank siding?

Help! We own a zero lot line home (basically half of a duplex) that is due for a paint job, and the owners next-door don't want to paint their half. This leads us to only be able to paint to the middle between our two garage doors, which will lead to a hideous line where the colors change. Sadly, this is the main view from the curb, leading to a nasty curb appeal.

I was hoping to install a 2x4 or some sort of decorative molding (ideas?)to the middle where the paint will cut off, and paint it the trim color in order to make the line down the middle less ugly. Could I install a trim piece over the existing hardiplank and lap siding, or would that create a problem? In other words, would I need to take down or cut the existing siding, or can I just put a piece of wood on top? How do I do it?

Sorry, I am really new to all of this.

In regards to a paint, I am leaning toward an earth-tone green but please, please, please give me your suggestions as I'm really not sure what to do.

Thanks!

 

Have you checked with your HOA? I've painted quite a few condos/townhouses and separate owner duplexes and usually the HOA has to approve any color change. Assuming it's ok to change the color, I'd consider painting the entire front of the garage - either your new color or if that doesn't look right, an accent color that would go with each color.

 

Either that, or have a big sign made and post it on your side with an arrow saying "Joe's side, ugly ain't it?" As Marksr said, it is always best to come to some amicable agreement, even if it means you buy the paint and paint it. You are looking to improve the looks, and I don't see how they could argue with that deal. Also, the HOA thingy may get sticky as well. Putting a dividing 2x4 or other trim down the middle only accentuates the division, so I wouldn't do that, either.