world, northeast United States, there are rocks and more rocks. If you are a gardener, the urge to combine rocks with plants is a natural one. This endeavor can begin a lifelong love of rock gardens as it did for me. And the one thing that I have discovered is that there are as many styles of rock gardens as there are rocks. It is all dependent on what you want and where you live. They can be expansive and dramatic or small and quiet. They may be located along a road, by the beach or in an urban backyard. In this chapter, I describe various rock garden styles and focus on the rocks and their placement.
Heat-loving plants such as agave (Agave americana) and Mexican feathergrass (Nassella tenuissima) thrive in the Gravel Garden in Chanticleer, a Philadelphia-area “pleasure garden.” Planted on an open slope, the Gravel Garden features granite steps, stone benches and gravel mulch that surrounds heat-loving, drought tolerant plants.
In rock gardens, the stones are the show. Their character may instill a feeling of a “savoring of the wild,” as H. S. Adams noted in his classic book Making a Rock Garden. In these gardens, rocks of all sizes and textures are set solidly into a natural setting with few straight lines or symmetry. They need not be complicated and are basically a habitat where plants and rocks co-exist. Here are a few ideas:
• A single existing boulder can be enhanced with a few additional rocks scattered nearby.
• A steep stony bank or outcrop can be planted up with some selected plants.
• A small rocky channel can run through an expanse of carefully placed rocks and succulents.
• A rocky hill can become a showcase for a collection of plants and stones.
Where to Locate a Rock Garden
The recreation of a mountainous rocky landscape was a popular endeavor in the past, when the classical advice was to set a rock garden away from the house and beyond the outdoor living area. But today, current styles have widened beyond the original alpine model and rock gardens can be established wherever you want. You are free to create what you like – where you like – with the understanding that, above all, rocks are the essential component. Even the name has changed; rock gardens are now commonly called rockeries. This moniker embraces all kinds of man-made rock environments.
Rockeries can fit in with the most irregular of sites, such as hot, rocky outcrops or forgotten side yards. It does not matter if there is sun or shade because rocks withstand any environment. The plants, however, must be suited to the light conditions you provide. The stones can be accompanied by sun-loving sedums or by a collection of hardy shade-tolerant ferns. A cautionary note: do not create a rock garden beneath a tree with greedy or inhospitable roots or dense shade such as a Norway maple (Acer platanoides). The roots may fight with the plants for water and prevent the rocks from being set deeply into the earth, while the leaves may cast so much shade that few plants can thrive.
The rock garden in Bartholdi Park, part of the U.S. Botanic Garden, located in Washington, D.C., is an example of the “hill and crest,” where the land slopes up to show off the rock garden denizens.
This colorful rock garden was created by Chris Hansen, plant breeder and hybridizer of SunSparkler® Sedums. The succulents and perennial flowers share the spotlight with the beautifully placed rocks.
Rock gardens can be located to act as a distinct break between other outdoor areas. For example, a garden of stones and plants may break up a long, monotonous walk or become an interesting destination in a hidden corner. You can create a rock garden on an existing slope or, with a little imagination, you can mound up some soil and make a small rise with rocks set within. This follows the “hill and crest” ideal, where rocks of varying sizes are set in a slope behind and above each other. It is a good idea to plant a backdrop of tall plants to show off this scene. You can also weave a rock or mulched path through the garden. That is what I did in the following example, described in the next few pages.
Did you know?
The art of the stone arrangement in Japan is called sute-ishi. ‘Sute-ji’ means build and ‘ishi’ means stone. It was considered the main element of a gardener’s work.
Sequence for Making a Flowering Rock Garden on a Small Slope
If you have a small slope and a supply of stones, you can convert it into a rock garden featuring low-growing flowering plants. In one overgrown hillside garden, I did just that, rearranging some existing stones and adding larger rocks from the site. You should add several larger stones to act as anchors to give a garden some visual weight and create interest. In this garden, I installed a curving narrow path leading through the rocks and plants. It is for tending to the plants and it also leads the eye through the garden. A small path is a good way to create a unified scene. Here is the sequence we used to renovate this small rock garden:
The rock garden before we started. Rocks are scattered around without an overall composition. There is no backdrop of taller plants to bring the garden in the foreground in focus.
The rock garden during the transformation. You can see the curving path with small rocks used as steps. Some larger rocks were brought in, smaller rocks were rearranged and we planted small plants around them. No backdrop plantings have been installed.
1. Stockpile the stones
First, we dislodged the rocks from the hillside garden and stockpiled them nearby.
2. Bring in some large stones
We brought in a few larger stones from another part of the property. We used a tree dolly, similar to a hand truck, to move the large rocks. I always try to use rocks from the area, if possible, because they are “at home” here. Also, try to use a single type of native rock, of the same color and makeup, for a cohesive appearance.
If you buy stones from a quarry or stoneyard, select stones when they are dry and not silt-covered so you can know the real color of the stone.
3. Dig up and save existing plants
We carefully dug up the existing small plants and set them aside. We mulched them and watered them for safekeeping.
4. Lay out the path
I laid out a narrow curving path leading up the rise with “marking” paint (this looks like spray paint but is specifically for marking the ground). Note – you can always redo your markings, so be free when you do this and then step back to review. If you don’t like it then erase the paint and try again. We removed a few inches of soil to denote the path and tamped the earth with a tamper.
5. Cover the area with good soil
I applied a thick layer of good soil over the site. If you have a sunny site, use a soil
