It is a simple fact that the majority of plants need a nice nutrient rich place to set their feet. Most plants crave lovely loamy soil with plenty of fertility and just the right amount of moisture and drainage. This is why rocky spaces can be so challenging. Rocky areas are dry, low in fertility and tend to conserve heat, which can make them too hot for some plant’s tastes. This is a laundry list of potentially unfavorable traits in the eyes of a plant. Successfully growing in rocky soil can be done if you amend it to increase nutrient content or if you simply choose plants that grow in this type of soil. Here are the top 5 plant types for rocky soil conditions.
1. Herbaceous perennials. Rocky soil can be hard for plant roots to get a footing into. Shallow rooting plants and those with tough, tenacious systems are the optimum choice for such areas. Herbaceous perennials are often the perfect choice for rocky soil. They will need a little TLC while they establish but can thrive for years once they are mature. Start with these:
- Butterfly weed
- Epimedium (shady rocky areas)
- Oxeye Daisy
- Rose Campion
- Black Eyed Susan
2. Herb plants. Herbs are also perfect for the rocky soil regions of your landscape. Sages produce lovely flowers while oregano will colonize an entire area quickly, producing bee attracting blooms. Catmint not only attracts the local felines but makes an excellent tea for you.
3. Succulent plants. When you think of areas of the world with rocky soil, what comes to mind? Deserts. Desert plants, such as succulents, are uniquely adapted to low nutrient soils. Sedum, Sempervivum, and larger plants like Yucca and Agave thrive in this soil situation. These plants won’t work for many northern gardeners, as they can be frost sensitive, but temperate to warm region gardeners will find them useful. Ice plant is another succulent that has brightly colored flowers and will enliven the rocky regions of your garden.
4. Small trees and shrubs. Trees and shrubs offer dimension to the landscape but often need deep soil in which to root. Many of the juniper species can survive in rocky soil, however. These include creeping Juniper, Chinese Juniper and Japanese Juniper. For larger “bush” sized plants, many of the ferns that are native to your region will provide lush greenery in rocky soil. Other options for larger plants are Ninebark, Sumac and Bladdernut. Each has a different season of beauty well into winter and are hardy in low nutrient soils.
5. Ornamental grass plants. Ornamental grasses may also be suitable for your rocky soil. The lovely Prairie Dropseed, when planted en masse, produces a sea of waving foliage with accompanying whispers in the wind. Little Bluestem is an exciting clumping plant with bluish foliage at the base and bronze fall foliage. Coastal grass plants have to be tenacious when clinging to rocky cliffs and beaches. Dune grasses have shallow rooting systems and have an airy elegance and movement that is exciting in the home landscape.
There are many choices out there for the rocky soil predicament. Reach out to your local extension office for native and zone appropriate choices in your region. Doing so will ensure you have the right plant for the site and growing conditions.