GARDENING WITH ROCKS
By Trey Pitsenberger, co-owner Golden Gecko

Foothill gardening often means working with or around rocks. These rocks can be a pain when you want to plant and the hole you dig has a large rock that is impossible to move. Other times the rocks that project above the ground can provide interest and a background for some fun plantings. In many parts of the state people have to go to great trouble and expense to bring rocks into their landscape. A couple recently paid $80,000 to have 40 tons of moss-covered stones and boulders arranged in the sloping front yard of their Mill Valley, Calif., home. The rocks form a streambed, waterfall, pond and curving staircase from the street. About 70 different species of plants fill niches within the rocks. The husband, an attorney, describes the craggy contrivance as his “mini-Yosemite.” That group of rocks you in your yard may be more valuable than you thought.

When you are faced with a variety of large rocks in your yard you can choose certain plants that will highlight the roughness of the rock while softening the overall scene.

Cascading plants are often ideal for use around rocks and rock outcroppings. Ponds and waterfalls made with natural rocks will also benefit from cascading type plants. Some of the more common cascading plants like Trailing Rosemary (Rosmarinus officianalis ‘Prostratus’) or Verbena are nice, but there are so many other interesting plants that trail or cascade. Some of my favorites are trailing or cascading conifers. Conifers are needled plants most often associated with trees that grow quite large. There is also a large selection of trailing conifers. One of the most beautiful is the ‘Prostrate Blue Spruce’ (Picea pungens ‘Glauca Prostrata’). This powder blue spruce will tumble and spread through rocks becoming quite the eye catcher. The Japanese Garden Juniper (Juniperus procumbens ‘Nana’) is another conifer that will trail over a wall or rock, clinging to the side creating a waterfall effect. To add some bright yellow to the rock garden try the ‘Motherlode’ Juniper (Juniperus wiltonii ‘Motherlode’). This plant cascades like the Japanese Garden Juniper but is bright yellow in the summer and has plum highlights in the winter.

Sometimes it’s nice to put rounded plants that can be tucked next to large rocks. The Mugo Pine( Pinus mugo var. pumilo) is a nice choice. Growing tight to about three to four feet tall and six feet wide it is bright green in color. To get the same affect in blue try the Montgomery Spruce (Picea pungens ‘Montgomery’).

One effect that works well near rocks is to plant up close to the rock a plant that has a strong vertical effect. One of the most commonly used plants is the Lily of the Nile (Agapanthus). This is the sword shaped plant with the tall stems topped with a blue flower in the summer. Fortnight lilies (Morea irriodoides) also have sword shaped leaves but with white iris type flowers on tall stems. The dwarf flax (Phormium) is available in different shades of red or yellow and only grows three of four feet tall.

If you are lucky sometimes rock out croppings lend themselves to becoming a part of a pond and waterfall. With the flexible rubber liner available nowadays you might be able to create a watercourse that can weave is way through the rocks to tumble down into a pond. You may have to add rocks to create the ultimate effect you desire, just be sure to keep it natural looking by matching the type of rocks.

Living in the foothills has its advantages. Most people would not have thought that large rocks and boulders would have been one, but with the right attitude and imagination you can create a wonderful scene, for a lot less than that couple in Mill Valley.