Often I am asked, "How do I put together the perfect container?" or "My pots are always flat and boring, what do I do to make them pop?". The process is all about the "-illers". A stand-out container is one that contains a "thriller", a "filler", and a "spiller". Let's break each one of these down and give examples of each.
The thriller is your centerpiece. The stand-out, single plant typically placed in the center or the back of a container. This plant is usually the tallest among the container plants. Most people see this as a spike or grass but there are many other options for the thriller. Some of my favorites are Black N Blue Salvia or Wendy's Wish Salvia, the various purple fountain grasses, elephant ear, Verbena bonairiensis, gaura, or even a climbing plant like black-eyed susan vine (with a trellis of course).
The filler is the plant that covers the soil and literally fills in your container. A filler is usually around half the height of the thriller and forms a nice mound. In your standard Memorial Day or old fashioned "spike, geranium, petunia" container, the geranium would be your filler. Geraniums are great (especially some of the newer varieties), but there are many fillers you can choose from. Mounding petunias (Crazytunia, Dreams, Madness series), impatiens, begonias, gerbera daisies, lantana, snapdragons, and lots more.
The final component of a container is the spiller, the plant that spills over the edges of the container and often times covers the container itself. The most common spiller is probably the petunia. These are the Waves, Supertunias, Cascadias, Headliners, etc. Many people will bunch these all into "waves" but Waves is a brand name. Other great spillers are sweet potato vines, trailing verbena, licorice vine, calibrachoa, vinca vine, scaevola, torenia and still many others.
The following photos and descriptions show off some of these possibilities, but keep in mind, possibilities are nearly endless. Be creative, and enjoy it! Happy planting!