Guide to Companion Planting

How to use shape, color and texture to create a showcase quality garden.

  • Shape
  • Color
  • Texture

Companion plants are plants that balance each other on some level. They can be either contrasts or complements; this works on many different levels. Let’s look at some different ways to link plants in the landscape.

Flower Shape

This is the most important category. Flowers come and go, and foliage complements are often not apparent at a distance. Strong vertical plants can be contrasted with horizontal plants. For example, an arborvitae with a pointed vertical shape would be well contrasted by a Mariesii viburnum, which has a very horizontal, rounded appearance (the round also contrasts the pointed).

To provide continuity in the landscape, you need complementary forms as well. A rhododendron would be a great shape to complement the viburnum, or a series of arborvitae can complement each other. Complements help carry the eye easily across the landscape; contrasts call attention to themselves. The well-balanced landscape needs both.

Contrasts Hosta and iris, dwarf Alberta spruce and azalea
Complementary Miscanthus and daylily, potentilla and spirea


Flower Color

The color complements and contrasts in the garden landscape are the focal points of the garden for the average viewer. Complementary colors create visual differences that the eye takes in easily. Many gardeners today are fond of the softer, pastel shades, i.e., pinks, soft blues, lilacs, etc.. The hotter colors, such as yellow, red and orange have such a strong visual impact that they have a tendency to dominate if not used sparingly or balanced with a strong blue or purple.

It is very difficult to make a smooth transition between hot, bright color and cool, soft color. A good rule of thumb is to avoid using hot with soft. Hot and cool colors can be contrasted, but it’s tricky. Softer shades of red are a great way to transition between hot and soft areas, and our greatest ally in blending any colors is white. White goes with everything!

Remember, green is a color too. In a shady area, the best color contrasts are often the different foliage colors. Varigation is a great color variance. When we think of color, we have a tendency to think only of flowers, but foliage, stems and berries are also great ways to use color in the garden, especially for winter interest.


Red monarda and Delphinium (blue)
Black Knight buddleia and Black-eyed Susan (A FAVORITE)
Creeping Phlox, Emerald Pink and Blue Clips Campanula (soft)


Pink garden phlox with purple coneflower (soft)
Red monarda and Coreopsis ‘Moonbeam’ (hot).

Plant and Flower Texture

Plants vary greatly in the way they present themselves in the landscape. To go back to our pairing of arborvitae and viburnum, the arb presents a very solid, finely textured form that is well balanced by the loose, coarser look of the viburnum. The fact that the arb is evergreen and the viburnum deciduous works well; needles contrast leaves, and in winter sticks contrast foliage. If our arb was in the background and the viburnum in the middle, a low evergreen broadleaf (say a boxwood) would bring everything together.

Now our arb is complimented by another evergreen, and still contrasted by foliage types. The viburnum works well with the boxwood because of the contrast in foliage (the huge difference in leaf size, as well as the deciduous/evergreen variance) and the complement of shape (both are rounded forms). Distinctions between leaf sizes are your best bets for textural variation and plants that contrast on some other level are always your best bet for complements.


Junipers and grasses, ferns and hosta


Hollies and rhodies, iris and daylilies


It’s all well and good to talk about the wonderful contrasts between a dwarf Alberta spruce and a saguaro cactus, but these two are not going to work together in the garden. We must balance our design choices with an eye towards compatibility of environments.

The shade garden is a good example of where our plant palette becomes restricted; there aren’t as many good flowers that do well in shade so we have to rely more on foliage, shape and texture. A seashore site will require us to think first of salt tolerance and then our other design components. The most important aspects of the environs are water, soil, and available light, but keep other factors in mind, such as wind, salt, siting (the north side of a house is usually full shade) and pests. Hostas are one of my favorite plants, but if the deer are regular feeders in the yard, I might as well plant a salad for them.


My favorite way to link plants in the landscape is by choosing plants to form specific communities. A butterfly garden uses all the design structure we’ve discussed already, and adds the interest of attracting creatures with a beauty all their own. Rock gardens can combine plants from the woodies and perennials to transform a sandy, rocky site into a miniature oasis. Particular types of plants, like roses or herbs can be gardens unto themselves, or you can combine wide varieties of plants, such as a native garden.

This all can seem very complex at first glance. But as your plant knowledge expands and you gain further understanding of color scheme and garden environments, these choices become second nature. Everyone develops their favorite combos; find yours and plant them that way! Pass on those successes and always keep an eye out for the new combos to try in your garden. The best combos can come from pure serendipity in the strangest of places; a memory from a vacation or the depths of the imagination, but they are the difference between a good garden and a great one.