Man-made earthworks create areas with special microenvironments, just as natural land forms do. These can be warm spots for chilly weather use, cool hideaways for escaping the heat, or places where the wind blows around or through (to discourage mosquitoes perhaps). Carefully planned, they can add to the comfortable use of outdoor living spaces and help warm or cool a house. Created thoughtlessly, they can make terraces uncomfortable and rob walls and roofs of energy.
The microclimates of these spots require plants adapted to their particular temperatures and conditions. For instance, in a hot sunny corner, made to capture winter sun, the plants will have to tolerate sun-scald. They will also have to withstand summer heat and drought.
For this kind of hot in frost-free areas, desert plants can be used with rocks or driftwood, requiring little care. Or a bed of blooming aloe, natal plum, hibiscus, and Madagascar vinca will give year-round bloom and fragrance. (Natal plum has thorns and requires pruning but is vigorous and fragrant.)
In cold climates, a sunny pocket could be planted with Japanese black pine, juniper, cotoneaster, creeping thyme, and daffodils. Such a planting palette will require little maintenance.
A cool, sunless pocket requires shade-tolerant plants. In the North, these might be holly, andromeda, Baltic ivy, bulbs, dogwood, and redbud trees. Azaleas and rhododendrons grow well in the shade, but need good light to bloom well. Swamp azalea (A. Kaemptferi), a woodland plant, is one of the few that blooms in full shade.
In the frost-free South, a shady pocket might sport the giant philodendron vine called Monstera deliciosa, creeping fig (sometimes known by its more exotic name of Zanzibar ivy), Brunsfelsia (with its heavy, sweet night odor), ginger, Agapanthus, and caladium lily.