What Goes Where? How to Design a Container Garden

The hardest part of gardening is deciding what plants to use. What plants go together? What about color? With the vast array of choices, where do you begin? The whole process can be overwhelming.

As I’ve mentioned previously, the basic container design is Up, Out, Down. Another way to look at it is "thrillers" or the focal plant, "fillers", mounding or spreading plants and "spillers", trailing plants. Varying the heights, growing habits, color and leaf shape of the plants used is what gives the container interest and makes a successful planting. Of course, there are containers that work well with a single plant and can be stunning but when you do combinations you don’t want the plants competing with each other. For example, if all the plants are upright, the container will look empty at the soil level. Using all trailing or spreading plants will look flat. Mounding plants do work well in a pot but can be boring unless in a grouping.

Good choices for the thriller or focal plant are taller, upright plants such as coleus, grasses, and taller varieties of petunias, snapdragons, zinnias and marigolds. Fillers include alyssum, trailing verbena, some trailing petunias, oxalis and smaller varieties of petunias, snapdragons and marigolds. Good trailers are vinca vine, creeping jenny, calibrochoa, bacopa and sweet potato vine.

So where do you start? I always start with a plant I love, something that catches my eye or that I just have to have. This can be any sort of plant. Sometimes I start with the focal plant, sometimes with the filler. It doesn’t really matter but having a jumping off point, a plant or color you want to have, makes choosing companion plants a whole lot easier.

One of the plants I love is the Global Merlot ivy geranium. I’m not sure if it’s the color of the blooms or the name that I love more but when I saw it, I knew I had to have it. So what to put with it? An ivy geranium is what I call a spreader. Some will call it a trailing plant but its growth habit is more straight out, filling in the soil line nicely. In this case, I started with the filler so I now I needed a focal point and a trailer. I literally walked around the greenhouse, carrying my plant and holding it up to others to see how it looked. It’s not unlike putting an outfit together. I found a sun coleus with burgundy and lime green leaves. The burgundy played nicely off the deep red blooms of the geranium and the lime green edging led me to the Marguerite sweet potato vine. One plant leads to another. There is contrast in growth habit and leaf shape but everything ties together.

It may take time to find plants that work together. What seems like a good idea in the greenhouse may not look so great when it all gets growing but that’s part of the process and what I think is part of the fun of gardening. Starting with a plant that you love and a basic formula does make the process a lot easier and increases the chances of creating a successful container.