THRILLER – SPILLER – FILLER is what I call a “fail-safe design technique” for container gardening.

I go over how to use it in my Container Gardening talks and classes.  Once you know and use the technique, your confidence explodes with creating stunning container gardens for your home.


Anytime I ask my class attendees if they have heard of “thriller-spiller-filler,” it amazes me how many have not. It is a widely used gardening term for container garden design, and the person who originated it, Steve Silk, probably wishes he had patented the phrase. Using the thriller-spiller-filler method works every time and is easy to do. It is what I call a fail-safe design technique. It is especially useful for beginners or those not sure how to structure the plants in a container garden or patio pot.


A thriller plant is basically the star of your container garden. It is a tall, striking, and bold plant commanding your attention in the center of your pot. Many people think of the using the typical annual spike plant as the thriller, but I tell my audiences it is time to step out of the little spike box and go for something really dramatic and grand. Tall perennials, ornamental grasses, or large tropical plants – and shrubs make excellent thrillers. The grander the thriller is, the more powerful your arrangement. It will draw your eye up to the design and elevate the composition.

When you visit your garden nursery center, take a look at the perennials, tropical plants or slower-growing shrubs to find your thriller. Don’t overlook house plants as well. For Connecticut gardeners, there are additional benefits to using these types of plants. For example, perennials can be removed from your container garden at the end of the season and be transplanted into your gardens for continued enjoyment. Tropical plants may be taken indoors as a houseplant or some may be stored over the winter for reuse the every season. And trees or shrubs can often last as a thriller in your container garden for years if stored properly, such as moving the container into a sheltered location over the winter.


A spiller plant is the “down and long” plant in your container garden. It cascades over the pot’s rim like a waterfall. This will soften the edge of your containers and bring the eye down. It relaxes the arrangement a bit. Annual vine-like or trailing plants, such as Ipomoea batatas (Sweet Potato Vines) and Lysimachia nummularia (Creeping Jenny), come to mind, but several trailing perennials work too. Many herbs make nice spillers, such as an oregano plant which will reach out along the edges. Many spillers are available. As you consider your co-star spiller plant, remember to look at the plant’s colors and form as well. A coarse leaf positioned next to fine leaf in a composition makes each plant stand out more. Avoid blending similar textures for they will get lost.

Colors are extremely important aspects to consider as you select your plants. Don’t play the “matchy-matchy” game, trying to find an exact color match. Instead focus on repeating or echoing the color of one plant in another plant’s blooms, foliage, or stems. These color repeats can be subtle. A variegated leaf of one plant may echo the color of another plant’s blooms in the container garden.


A filler? You guessed it. A filler is just that, it fills in and around the thriller and spiller plants. It is the “all-around supporting” candidate. It adds weight and mass to a design.

Think of plants with a bushy full look and shorter heights as compared to the thriller in the design. There are a plethora of options for fillers, and you may pack them into your container gardens. Remember to try to echo the colors of the other plants in the pot and use contrasting texture. You may use one filler, two or three, the choice is up to you.

An example is using Pennisetum ‘Princess Caroline’ as a the thriller with its broad purple blades, growing to 36” tall. This thriller will command attention. The tall perennial next to it could be a flowering Rudbecki hirta ‘’Moreno’ (Black-eyed Susan), reaching 12” tall, and showcasing mahogany-red flowers. It serves as a welcoming plant and echoes the colors of the grass like Pennisetum in its bloom centers. Color echoing is something you need to look for in your designs – it will unify the whole composition. As you select your thrillers, spillers, and fillers – consider color echos and varying textures.

In my garden talks, I go over examples and explain more on ways you may structure your container design – as there are other ways. You don’t have to use TSF, but it does work – every time.

Get thrilling – spilling – and filling. You will see yourself using it every season. So will everyone else commenting on how beautiful your container gardens are at your home.

Written by Cathy Testa
Owner of Cathy T’s Landscape Designs and Container Crazy CT
860-977-9473 (texts are welcome!)


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