When it comes to outdoor décor, nothing beats the beauty of a planter or window box bearing an exquisite arrangement. Whether you prefer a welcoming array of colorful blooms or something sculptural and statement-making, adorning your outdoor space with an eye-catching container garden will instantly add interest and make the area feel more inviting. Since there’s an art (and a science) to creating an ideal plant composition, we turned to Paul Kawoczka, co-founder of Philadelphia, Pennsylvania-based seasonal arrangement subscription service Enliven Planters, for guidance. Here, he outlines what to consider when composing a container garden.      

Remember: thriller, filler, spiller. “I’m not quite sure who coined this phrase, but it holds true,” Kawoczka says. What it means is any container should have a tall (approximately 1:1 ratio to the pot) interesting plant—aka, the “thriller”—to provide height and visual interest. Around the thriller, fill in with mounds of plants that serve as “fillers,” which can be flowering or foliage, that will add body to the composition. Last but not least, spillers are plants that cascade over the edge, adding depth and drama to the design.

Take texture into account. “Texture is really fun to play with, and often overlooked,” says Kawoczka. A way to visualize how texture can vary is to think about what makes a great holiday wreath vs. a boring one. A beautiful one will vary evergreen textures, mixing short, stubby needles (fir); long, fine needles; broad, shiny leaves (magnolia); webbed foliage (cedar); and fine, miniature leaves (boxwood). The same variation can be accomplished with annuals and perennials in a live container.

Keep your color palette simple. Color is what most people think of when they picture their ideal container garden. Keep it simple by choosing three colors and repeating them throughout the container. When purchasing your plants, I highly recommend buying ones that are in bud, and not fully bloomed yet. While the big, beautiful blooms are tempting, they can fade pretty quickly and leave you feeling disappointed a few days later.

Rely on repetition. Repeating elements multiple times in an arrangement creates balance. For planters, this means surrounding your thriller with multiples of the same types of fillers and spillers, all the way around the vessel. In a window box, this can easily be done by making the composition symmetrical. Put the thriller in the middle, and use that as your axis. Every plant you put on the left, mirror on the right.

Get creative with colorful foliage. No matter how much you fertilize, there will be times when your arrangement cycles out of its peak blooming. Using foliage in a variety of colors dramatically increases the interest of a container and extends the season for arrangements. There are hundreds of varieties to choose from in nearly any color imaginable.

Pick the right plants for the right place. Choosing the wrong plants for your pots is by far the number one reason plants die—shade plants will fry in the sun, and sun plants will get leggy and stop blooming in the shade. Be sure to check the plant labels when you’re shopping, as they’re usually color coded: yellow means sun, orange means part sun, and purple means shade. Any combination of the two colors indicates that a plant can do either. And when in doubt, ask an expert.

TSG Tip 212 from Paul Kawoczka, co-founder of Enliven Planters in Philadelphia, Pennsylvania. Enliven Planters is featured in The Scout Guide Philadelphia.