Hailing from the Mediterranean, oregano (ht to 30 cm) is a useful herb for cooking. I have never been too sure of the difference between oregano and marjoram: Origanum vulgare is called wild marjoram in the UK and oregano in the Mediterranean. There is an oregano species called Oregano majorana that some people regard as the true marjoram. As a garden plant, Oregano vulgare makes itself very much at home, spreading beyond its original appointed patch. You need to be fairly ruthless in reining it in every so often.
This gold-leaf version is an attractive plant in its own right, particularly in spring, when its foiage has an almost incandescent glow. It will tolerate part-shade, where the leaves will take on a lime hue. It is just as edible as its green-leafed cousin! It is not quite as sprawling as the common oregano but does expand sideways a bit, so every year I pull up the rooted pieces which have travelled too far. I cut it back hard in late winter. It forms a useful groundcover in sunny, well-drained spots and also looks effective spilling over retaining walls. Mine grows nearby some vibrant purple Babiana bulbs and the combination of colours I find compelling. It also looks good with blue flowers, as shown in the photo above. I cut back the foliage when it becomes tatty in autumn. The colour of the leaves makes it a useful addition to a summer salad. The tiny pink flowers of the plant, whilst not very showy, are attractive to beneficial insects, including bees and hoverflies. There are some very ornamental cultivars of oregano with stunning large flowers, such as 'Kent Beauty', but I have never had much success with these in my Sydney garden: I think they do better in a climate with a dryer summer.