By Karen Panter, Horticulture Agent, Commercial Greenhouse, Colorado State University Cooperative Extension
Many of us have a sloping or rocky (or both) area in our landscapes that requires some extra attention. One of the ways to build an attractive garden area is to use rocks and low-growing plants in a rock garden. There are many annuals that work well in this type of setting.
Let's assume that all the preparatory work in the garden has been done. This prep work should have included using rocks of the same geological type for the best effect. It should also have included soil amendments, such as addition of organic matter, and thought as to how the garden will be watered. Most alpine/rock garden plants must have good drainage.
Some rules of thumb for planting rock/alpine gardens include using many different types of plants, including annuals. Each type of plant should be repeated several times within the garden to create a more natural effect. Try not to overplant the garden so that rocks and mulch are covered up quickly during the growing season. Plant species that are low-growing and have a clumping growth habit.
Most of the plants that are best suited for rock gardens are perennials. However, there are a few annuals that fit in quite well with this type of landscape. Some of them include: dianthus (Dianthus Barbados), allysum (Lobularia maritima), portulaca (Portulaca grandiflora), and vinca (Catharanthus roseus).
With a little advanced planning and careful selection of plants, your rock or alpine garden can be full of color all summer long.
Photos: Judy Sedbrook.
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010