There's nothing more depressing than filling your tiny outdoor space with colorful plants only to find it transformed into a droopy, withered mess by mid-summer. Not everyone has a green thumb, or the time to tend a garden full of plants with disparate needs.

When it comes to low maintenance gardening, rock gardens are the way to go. They add shape, form, beauty and elegance without requiring constant attention. Like plants, rocks can be assembled haphazardly for a cottage garden feel or meticulously placed for a modern, geometric design. Combined with gravel, they can offer a calm, meditative oasis in the Japanese Zen style.

If the idea of a grey garden sounds dull to you, there are a huge variety of low-maintenance plants that can be easily cultivated in this environment. Add a range of mosses and ferns to the shady rock garden, or try flowering plants like larkspur, alyssum, yarrow or sedums in a sunny spot. Use dwarf conifers and evergreens to add verticality and a touch of color all year round.

Images: 1. & 3. Garden Design, 2. Daniel L. Hagerman, 4. Dan McCormack, 5. Suppose Design