When gardeners go to a nursery and ask, “What shrubs can I plant that don't require pruning?" they are bound to get a wide variety of responses depending on who they ask. Some shrubs are generally left unpruned because pruning reduces the abundance of flowers, while others just look best when left in a shaggy state, offering little reward for the effort of pruning. Another option is to peruse the selection of coniferous shrubs—most have a naturally compact growth habit and do not sprawl out into leggy behemoths. Below is a sampling from across the range of low-prune types.
Dwarf Japanese Cedar
There are dozens of dwarf Junipers, Spruces and other conifers that stay compact and small for their entire lives, but few are as elegant as Japanese Cedar. Known for its soft-textured foliage that forms a tubular shape along short, slightly drooping branches, it becomes tinged with a dusky bronze color in fall (though it is evergreen). 'Globosa Nana' is the most widely available variety, which grows slowly into 4-foot rounded mound. USDA zones 5 to 8.
Azaleas and Rhododendrons
This is perhaps the largest group of shrubs that are typically left unpruned. Azaleas and Rhododendrons naturally have an elegant, compact shape and look absolutely butchered when pruned—plus, unlike Roses, the more you prune them, the fewer flowers there are next year. Rhododendrons have large, glossier leaves than Azaleas and are almost always evergreen. They are best in cool climates. Azaleas thrive in warmer climates and have smaller leaves that may be deciduous or evergreen. Both come in a wide variety of colors—choose one that fits the space you have so you won't be tempted into pruning them!
One of the best no-prune shrubs is often overlooked as even being a shrub. Most gardeners classify Rosemary as an herb, but it is actually an evergreen shrub with many redeeming qualities besides its flavor and aroma. It grows very quickly to about 3 feet tall and then maintains itself around that size. Its needle-like leaves harbor pale blue flowers in late winter or early spring, which are a boon to bees and other pollinators. And perhaps its most important selling point is that it requires little to no water to get established. USDA zones 6 to 10.
In addition to the familiar white-flowering dogwood trees, there are several outstanding shrub-size dogwoods that are known for their colorful bark, including red and yellow twig Dogwoods. These are varieties of native Dogwood that are useful in naturalized woodland gardens where they can cover a lot of ground and provide habitat for birds. They could be pruned, but that would go against their wild, rambling nature. Plant them where they have room to spread and enjoy their four-season beauty. USDA zones 2 to 8.
Like dwarf Japanese cedar, Daphne naturally has a round, compact shape. And like rhododendrons and azaleas, it flowers less the more it is pruned. Daphne's pinkish-white flowers are a show stopper when they appear in mid to late winter and fill the neighborhood with their ethereal fragrance. Use it as a low evergreen hedge in a shade garden and as a well-behaved potted shrub outside your door during its bloom time. USDA zones 7 to 9.