I planted sage and oregano side by side several years ago and it is actually taking over my front flower bed. I love to dry it and give it away but I have plenty! Is there any way I can keep it from spreading further?
Pull some up and plant other hardy plants that will fight the takeover. lol I had the same problem with mint in the backyard. Its taken completly over. Now everytime they mow it smells like mint.
I had the same problem with oregano and mint, but I don't really see it as a problem. I drink oregano and mint tea every day, it is very good for you. You could just dig some up and plant something new to stop it spreading.
If I had that problem of spreading herbs I would cut a large oil drum in thirds after taking off the top and bottom, dig a trench around the plant and bury the container around it. Using small pieces of roofing iron ,wide planks or even plastic will contain it. You would then need to remove unwanted parts of the plant.
I have mine planted in a container on my kitchen window sill now. This keeps them from spreading and I don't have to go ouside to get any herbs while I am cooking. It is really nice to have them close by and I use them more often now.