Plants, Stones & Design Ideas for Building a Rock Garden

A Multi-Layered Rock Garden
A Multi-Layered Rock Garden

One of the most interesting DIY projects is to design and build a rock garden. It gives you an opportunity to get creative and exercise your imagination, the end result is worth the effort. What does a rock garden look like? Check out this pic.

It can be something as simple as a ring of large stones with flowering plants in the center or as massive as a five layer stone dune with a variety of foliage and flowers; you can of course take the middle path and build a two-layer rock garden as discussed in this article.

A few pointers to keep in mind while building a rock garden are:

    1. A natural slope or lifted terrain in your garden is an ideal spot to build a rock garden
    2. It looks more aesthetic if you use rocks of the same geological type. For example if you use granite just prevail with granite across the whole structure.
    3. The structure should allow for good drainage or else the water will get logged in the crevices and form puddles.
    4. Go for variety when it comes to the plants you will be employing. Alpines, orchids, perennial flowering plants, herbs, compact evergreens and ornamental grasses can all be combined together as plants for rock gardens. Such a combination gives it a more natural look.
    5. Keep the rock garden small, so its easy to maintain.
    6. Choose plants that spread slowly. Usually plants that are low-growing and have a clump forming habit are a better choice.
    7. The focus should be more on foliage and stems rather than flowers. Choose some plants sheerly for their foliage variations and texture rather than for their flowers. Blooms do add beauty so choose a few plants for their blooms also.

Come up with your own unique rock garden ideas, there are no hard and fast rules here, as long as there are plenty of rocks and attractive plants around.

Planning the rock garden

Do the basic planning first, basically it involves deciding on the rocks or stones you will be using and the plants that will be a part of the garden.

Choosing the Garden Rocks

Try using rocks that are native to your region, for example if you live in Colorado go in for the native granite called the “moss rock”. You don’t have to choose any particular type of stone, just make sure they are the same shade of color. Some popular stones used in building a rock garden are: Granite, gravel, marble, sandstone and limestone. Avoid using soft stones or porous stones as they’ll suck water out of the soil.

You can make it into a fun project to drive over to some hilly areas and collect large stones and pebbles or you can purchase the rock garden stones locally from a nursery, rock dealer or some landscape contractors. Many rock garden designs involve using white gravel, you don’t have to stick to this idea just get creative.

Use rocks in a variety of sizes. Combine really large ones with small stones and medium sized garden rocks. Types of pebbles and smooth rocks in the crevices and flat stones at the bottom of the patch would be ideal.

Choosing Rock Garden plants

Candytufts in Rock Garden
Candytufts in Rock Garden

Before you start selecting the plants, some planning is in order. The basic need is to find the right color combination between the rocks and the plants. For example, if you have red sandstone as your rocks, you should consider plants that have red tinted foliage, stem or flowers and some with contrasting colors like white and yellow.

Be sure to exhibit some contrast in sizes also, don’t plant all puny vegetation or all tall ones. Mix and match small plants with floppy tall grasses and perennials.

All the plants for rock gardens should be able to tolerate a well-drained soil. The water will tend to seep through and percolate through the soil between the rocks, in sunny weathers and you have some pretty dry conditions – so these plants should preferably be drought tolerant also.

In summary try bringing some variation in the below three aspects

  • Color of flowers & foliage
  • Leaf-Texture
  • Plant Sizes

Do this planning before you go to the nursery. Once you are at the nursery go about picking the plants that fit into your scheme.

Use two to three plants of the same variety to give a more flowing look. Using different types of plants in a small area will end up looking really messy and discontigous. For example, if you plan on using scotch moss and wood spurge, plant 4 scotch mosses along with 2 wood spurge in a small patch.

Some good plants for rock garden are as below ( r stands for recommended)

  • Scotch mass (r)
  • Daffodil
  • Lamb’s Ear (r)
  • Wood Spurge(r)
  • Sheep Bur
  • Dwarf Yarrow
  • Stonecress(r)
  • Catsfoot
  • Rock Jasmine(r)
  • Alpine Aster
  • Shooting Star
  • Whitlow Grass
  • Green Carpet(r)
  • Candytuft(r)
  • Oregano
  • Primrose(r)
  • Penstemon
  • Stonecrop
  • Speedwell
  • Pasque flower(r)
  • Snow in Summer(r)
  • Carpet bugle
  • Chocolate Chip
  • Snowcap Rockcress
  • Basket of Gold(r)
  • White Clips(r)
  • Snow Angel
  • Dwarf Iris(r)
  • Dragon’s Blood
  • Hens and chicks(r)
  • Lemon Thyme
  • Corsican Violet
  • Mountain Zinnia
  • Valley Lavender(r)
  • Rockery Orchid
  • Phlox

Valley lavender, rocky mountain zinnia, basket of gold, rock jasmine, pasque flower, candy tuft and daffodils make for attractive rock garden flowers.

Implementing a Rock Garden

This is basically a four step process

Preparing the patch

Look around your garden and determine the best patch for your rock garden. It can be a corner or the center of the garden, it can be a barren patch or the middle of a lawn, it can be a slope or a creek – any patch can be converted into a rock garden. If there is a natural sloppy patch in your garden then it would be most ideal, but it is not a necessity.

Grasses or weeds around the patch would have to be removed, just till them up and clear the area. Throw in some dirt and loose sand to cover the patch before placing the stones.

If you don’t feel like tilling the area, just put a layer of newspaper on top of the patch and shovel in some dirt on top of it. The newspaper will smother the vegetation beneath and it will decompose with time.

Layering the rocks

White Gravel Rock Garden
White Gravel Rock Garden

You don’t need to follow any fixed ideas for a rock garden but you will need to decide if you want a single layer of rocks, two layers, three layers or even more. A two layer stone garden is easy to build and manage, if you feel ambitious you can add more layers. Here we will discuss how to implement a two-layer design for a rock garden.

The first course of rocks will determine the periphery of your rock garden. Use really large rocks for the first layer. The first layer is usually hidden by the top layer, so reserve your best rocks for the top layer. You can form a square, circle or some ambiguous shape depending on the space available, bear in mind that a circular rock garden looks a lot more elegant than a square one.

The first course of rocks should be buried half-way into the ground to give it a more natural look. It also provide a better foundation to the structure. Position the rocks to minimalize soil erosion.

Adding the soil

After you lay out the first layer of rocks, shovel in the soil. If you have clay soil at your disposal, mix in a good portion of sand to improve its drainage. Mix in the fertilizers and compost before you shovel it in. A slow release fertilizer is the best option with rock gardens.

Planting your plants

Start planting on the soil. Let your imagination determine the location of your plants, just make sure there is some unity in the varieties and some variation in the colors. Before you remove the plants from the containers you can do a test run by placing them at the desired spots.

Once the plants are in place, add the second layer of rocks. These rocks will also act as the mulch for your plants so use a combination of small pebbles, medium-sized rocks and broken rocks to cover the area. The end product should look full of rocks with a spread of plants in the spaces. Avoid using a bark or cocoa or any other types of mulch. When you build a rock garden use stones for mulching, just make sure the stones you use fits in with the color of the foundation rocks.

If a plant grow too large you can consider dividing it or transplanting it elsewhere.

And there you have it, a beautiful construct of stones and plants to adorn your landscape. As you can see building a rock garden is not only fun and creative but allows you to add a new dimension to your landscape.