It's probably privet. Where do you live? This stuff does well in the Northeast, but will lose most of its leaves in winter. In the south, boxwood is great but very slow-growing, fake boxwood (Ilex) grows a lot faster, but isn't as beautiful as real boxwood. It is a lot cheaper though. You have to do A LOT of trimming to acheive this look. My dad is kind of obsessed with his hedges and trims them weekly.

What kind of siding does it have?

The house siding is cedar, sorry it took so long to respond I missed this series of questions.
The hedge is a privet. It has a pool fence within it. The privet is two rows of plants with the fence in the center.
Becky is correct, I would trim the privet and boxwoods three times a year.