Rock gardens are unique landscape features that showcase a variety of interesting plants and rocks. They are versatile and adaptable to any size yard. A simple design is a few plants and some small or medium-sized rocks. An elaborate design is multi-level with large boulders, pathways, plants of all sizes, sculptures or a water feature, such as a pond, stream or waterfall. Gardeners frequently choose succulents for rock gardens because of their tolerance for drought, full sun and poor soil. Succulents match the low-maintenance appeal of a rock garden.
Characteristics of Succulents
Succulent is the name for a varied group of plants that have the ability to store water in their stems, roots, fleshy leaves or petals. Most succulents grow slowly and have little need for pruning, staking, fertilizing or pest control. Succulents come in a wide array of shapes, sizesand colors. Some have bright, showy flowers and spines or needles growing from their main stems, branches, leaves or petals.
Diversity of Succulents
Popular types of succulents are agave (Agavaceae), aloe (Aloaceae), ice plant (Aizoaceae) and cactus (Cactaceae). 'Hens and chicks' (Sempervivum tectorum ) is a well-known succulent that thrives in U.S. Department of Agriculture hardiness zones 3 to 8.
There are thousands of succulent cultivars found in over 40 different plant families. Every shape, size and color of plant is found among succulents. Agave is the most diverse group, having plants that are perennial in almost every climate zone of the United States. The cactus family has over 2,000 species growing from the Arctic Circle to the United States' border with Mexico.
The ideal place for a rock garden is a hillside, natural slope or terrace. Building on an incline facilitates water drainage, and allows the topsoil to dry quickly. If a terraced area or hillside is not available, create an informal raised bed garden with irregular curved sides.
Select a location that receives full sun most of the day. Full sun helps soil dry out and minimizes the risk of diseases caused by mildew. Choose a site away from lawn sprinklers and residual dripping from rain, such as under eaves or tree limbs.
Stay clear of trees as they absorb a great deal of water, create shade and have lateral roots that could invade the rock garden. Do not overbuild. Rock gardens require maintenance, so start with a size that is easily manageable.
The beauty of a rock garden lies in its ability to blend with surrounding scenery. A rock garden placed in the middle of lush green grass looks out of place. Rather than having grass edge your rock garden, provide for an 18” perimeter of gravel to serve as a transitional area or footpath.
Decide ahead of time which succulents to plant. If you prefer to add some formality to the garden, use succulents in a single group such as all agaves or kalanchoes (Kalanchoe blossfeldiana). If you prefer a variety of plants, choose cultivars with some characteristic in common, such as bright flowers or leaves with appendages of hair or spines. Consider sectioning off areas to feature a collection of related plants. Use plants with varying heights, placing tallest plants in the background.
With paper and pen, design the plan for your rock garden. Include the shapes, sizes, dimensions and placements of every element of the garden. Allow room for the plants to grow and mature.
Use rocks of one geological type to lend a natural look. For large gardens, incorporate one or more boulders 200 pounds or larger. Bury the boulder with 1/3 of its mass underground.