Young shoots of ‘Dwarf’ oregano with roots can be easily clipped from the mother oregano and transplanted. I propagate most of my oreganos using rooted side shoots that develop in early spring when the plants start the new season. Established plants generally send out new growth all around their edges. If you lift these side shoots, you will find some have developed roots. Clip off the baby plants that have begun to root. Put them in pots or replant them in the garden.
If rooted shoots are absent, you will need to propagate the plants by taking stem cuttings of new growth. Cut just a little below where the stem feels slightly stiff and place the cuttings in moist sand or vermiculite or a combination of both.
Keep the cuttings misted for a week or two until they can take up enough moisture through the stem, then keep the cutting bed moist. Roots should appear in four to six weeks. Using rooting compound and bottom heat improves results.
Oregano can be grown from seed, but the seedlings will vary in quality because they will be the result of random cross-pollination. This means you will have to weed out the inferior plants. If you take this route, sprinkle the tiny seeds on the surface of the soil and just barely press them in. Water carefully or mist the seeds with a sprayer to avoid washing the seeds away.
The seeds do best for me in soil temperatures between 50 degrees and 65 degrees F. When I plant the seeds outdoors, I cover them lightly with straw to keep them moist, then remove the straw once seedlings appear.