After many centuries of cultivation, myrtle (Myrtus communis) has not changed much. It was one of the more traditional plants for formally shorn hedges in Victorian gardens. It functions somewhat like a drought tolerant boxwood. Unshorn plants can grow as gnarly small trees not much higher than the eaves. 'Compacta' gets only about 3 or 4 feet high and wide, even without pruning.
The finely textured evergreen foliage is very aromatic and darker green than boxwood foliage. Individual leaves are not much more than an inch long. Not many of the tiny white flowers that bloom in summer develop if plants are shorn regularly. Unshorn plants that are allowed to bloom can produce small bluish black berries which might be messy on pavement. Foliar density is best in full sun. Shade can cause bald spots. Established plants may not need watering and might live longer than anything else in the landscape. -- Tony Tomeo