Likely as not, a large thicket of many plants that all look alike is in fact a multitude of clones from just a few plants, that have sent out root suckers. If one is willing to wait five to ten years, a low budget planting plan with clonal species can yield impressive coverage. Sumac clones can be twenty to thirty feet tall, and make a fine hedge. Scattered aromatic sweet fern (Comptonia) will coalesce to form a low spreading cover on a sandy slope. A few sweet pepper bush (Clethra) shrubs will become a a mass of white fragrant flowers in early summer. Patch-forming native woody species, that form large, even homogeneous masses are actually very well suited to formal landscaping, contrasting with isolated specimen plants. Other excellent clonal shrubs for use in landscaping are gray dogwoods, chokeberries (Aronia spp.) , and bayberries.
A knee-jerk reaction might be that with a few large clones, we have few species and low genetic diversity, not a desirable situation, ecologically. In fact these species form clones wherever they grow in the wild or human designed landscapes. From the perspective of insects, tree frogs, and birds, larger patches make for more energy efficient foraging. A flock of cedar wax wings will settle down to feed for an afternoon on a sizable patch of chokeberry or gray dogwood and the nectar from a Clethra colony is a significant food source for a bee colony. Its easier than hunting for widely scattered fruiting or blooming shrubs! Of course, taken to an extreme, a large monoculture or plantation often leads to pest infestations. Landscaping with clonal native woody shrubs is not only economical for us, it is energy efficient for the creatures further up the food chain.