A city garden, whether it be something as mundane as a window box or as sprawling as an empty lot outside your apartment building turned into a gleeful summer stroll, is a lively and much needed diversion from the drab gray walls and black pavement of the concrete jungle. However, it does have some challenges to overcome: poor soil and light issues. As a result, putting together a city garden requires planning and forethought.
While an empty lot presents plenty of room for a garden, it is still not much to work with. To counter this, you can use dwarf species of larger plants to give the impression of space. This idea works best in colder climates that receive moderate rainfall and little sunlight. A ground cover of zoysia grass appears natural, ideally with little hillocks and dips. Place dwarf pine randomly throughout, each with a ring of holly, shasta daisies, dahlias and sword ferns to give the impression of wild growth. Keep in mind this will require a significant amount of fertilizer and soil enrichment to see results.
A rooftop garden solves the issue of poor sunlight that ground level gardens might experience. It is essential to take advantage of this by using large, leafy green plants that can withstand wind and low temperatures to give the impression of your own personal jungle. Clearly, piling up soil for a garden bed is infeasible, as is using trees. Therefore, the primary ground covering should be mulch or cedar chips with decorative concrete stepping stones throughout. A raised central bed is perfect for a series of maypop plants, which provide all the rich color of passion fruit while still being resistant to cold. Stands of dwarf cranberry of bayberry set in pots can ring the walkway, acting as a wind buffer and giving a greater semblance of privacy. Cover the entrance with a wrought iron trellis, upon which night blooming jasmine can creep.
In hot, dry environments with sandy soil, a southwestern-style rock garden in an empty lot lasts longest. This can include a central bed of dwarf barrel cactus, agave and autumn sage for color. Barring this can be a decorative fence of rough-cut pine in the fashion of a cattle corral. Further out, make a walkway of interlocking Spanish tiles, upon which you can rest chairs made from water barrels. Polished river rock is ideal for the the ground cover, though gravel is cheaper. Use flowering bunny ear cactus, Texas red yucca and pineleaf penstemon for the outer ring beyond the walkway.