The idea of gardening in gravel is not a new idea. With concerns of water conservation, the whole concept of dry land gardening or xeriscape has become very popular, and gravel gardens lend themselves perfectly to these ideas. Not to mention the Japanese have been using gravel gardens for centuries in their contemplation gardens.
The physical attributes of gravel make it an excellent medium for gardening as it allows water to flow freely as well as the exchange of oxygen and carbon dioxide. It also encourages germination of seeds for self propagating plants. Gravel provides excellent drainage for plants that require it such as Mediterranean plants, herbs and succulents. Dry on tops but nice and cool below, gravel gardens also cater to alpine plants and encourage over wintering success. Rounded pea gravel is ideal for gardening and will often come in a variety of color tones. Crushed gravel works better on areas that will primarily be used as walking paths. Many plants that can tolerate dry conditions and well draining soil will thrive and spread in gravel gardens or beside gravel walkways. Here are a few worth trying.
California Poppies (Eschscholzia californica): An annual for full sun flowering from spring right through to fall. This is actually the official state flower of California. About 2 feet high with yellow or orange flowers, however cultivars can sport red, pink or cream flowers. They will usually re-seed themselves for next years garden.
Gaillardia: Striking plants with distinctive orange, red, yellow, often bicoloured daisy-shaped flowers. They mature into rounded, grey seed heads and prefer full sun.
Johnny Jump-Up (Viola): Blooming spring through to fall, they can grow in a wide range of conditions and can tolerate sun to part shade sites.
Sedums: A wide range of perennial cultivars to choose from. Excellent ground cover plants and larger border specimens.
Portulaca: An annual for full sun, carpeting the ground at just 4 inches high. Usually will self seed.