I think 'Italian" oregano is marjoram ((Origanum x majoricum) It is a very tough plant and can really spread. I started some years ago and now have to hack it back a few times a year. The flavor is much milder than greek oregano, but it'll do in a pinch.
We are learning agriculture anew and the focus now is on feeding the soil, not the plant. A local professor and his wife have written a series of books on the soil and the mycorrhizal environment. He's lectured locally several times.
https://www.amazon.com/dp/0393353370/?tag=hearthamazon-20
Also local is the foremost mycologist, Paul Stamets. He was a prof when I was in college.
http://www.fungi.com/about-paul-stamets.html
I've been managing a local test garden where we are exploring the effect of adding carbon via compost and biochar on plant growth. The garden started out as really poor clay fill soil that would only grow deep rooted, tough weeds. We're in the 3d year now and the turnaround has been fantastic, better than expected.