Sounds like Jill- over-the-ground - a pernicious weed. Don't let this loose in your garden or you'll regret it. I had it delivered to my door by the oil company, replacing some dirt they spilled oil on. That was 20 years ago and I'm still pulling the damned stuff out.

The herb sold as oregano by spice companies in the US is actually Mexican sage. The flavor is much stronger than Mediterranean oregano (the real thing). One can purchase real oregano plants, look for the words oreganum vulgare. I have a couple in my yard. They are attractive, small, compact bushes.

Oreganum vulgare is a small compact bush?? Not in my part of the world it isn't. It spreads widely - further than the horizon if you let it! Almost as bad as mint.

My 10 year old Oregano plant is at least 3 feet across.... and that's with digging it back every year. At least it hasn't migrated to other places in the gardens.

In my zone it's exactly as stated by lorna-organic: a small, compact bush. Dies back at the first hard frost and begins anew in the spring. Spreads very slowly.