Q.Rosemary growth rate
I’m based in George, South Africa (winter rainfall, semi subtropical climate). I’ve been struggling to get adequate growth on my propagated rosemary clippings, grown in containers. I’ve been researching, in vain, on how long it typically takes for clippings (approx. 3-5 inches each) to reach an acceptable size. My clippings root just fine and are very much alive, but I’ve seen only about 2-3 inches growth in the last 7 months. Is this normal? I know they are slow growers, but should it take this long?

Taking cuttings in spring when the plant is actively growing is the best time.
Using rooting hormone can help the process but it still can take a month or more to root the cuttings.
From their it can take several weeks or months to develop plants with good root structures.
Here is a link to refresh you on the growing requirements.
https://www.gardeningknowhow.com/edible/herbs/rosemary/how-to-propagate-a-rosemary-plant.htm