Designing Your Container Garden

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When planting a large container, also use large plants so everything is to scale.
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Old tires are hard to recycle , so if you have a few, you can use them as small "raised bed" containers for small trailing plants, with taller plants near the center.
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"Dragon's Breath" is the perfect thriller.
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A traditional "thriller, spiller, filler" container.
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“Practical Organic Gardening” by Mark Highland provides readers with a modern perspective to organic practices, methods, and products that any home gardener can enjoy.

Practical Organic Gardening: The No-Nonsense Guide to Growing Naturally(Cool Springs Press, 2017), by Mark Highland is a modern visual guide to growing organically. The book provides step-by-step photography and how-to projects so readers can take a hands-on look at updated popular gardening techniques. The following excerpt is from Chapter 10, “Organic Container Gardens.”

When selecting plants for a container garden, gather the plants together on a cart at the local garden center so you can see what they look like clumped together. Before buying, mix and match plants to arrive at arrangements you like.

Don’t be afraid to jam lots of plants together in the pot. If they fit inside the confines of the pot diameter, the arrangement will work. Keep in mind, though, the more plants you jam into a container, the more often you’ll have to water. Young plants will also grow up and expand, so make sure and leave some room for them to reach their full potential. If in doubt, ask a garden center employee how big your plant choices will get. If shopping in late spring, odds are the plants will already be grown up enough to get a good sense of their late-season size. You can always pull the plants apart at the end of the season and repot/repurpose them into other containers.

The best container designs have a variety of sizes, colors, and textures in them. When designing your container garden, you get to choose the details. Maybe you want all white flowers, or maybe you want all texture and no flowers, but there are no bad decisions because you are designing what makes you happy. Here are a few pointers for creating killer container garden combinations.

Thrillers, Spillers, and Fillers

Traditional container design theory says for maximum impact you should have the classic elements: thrillers, spillers, and fillers. One plant is chosen to be the center of attention, or the thriller. Spillers are plants that literally spill over the sides of the container and cascade down toward the ground. The fillers are there to add color or texture, completing the container by filling in around the thriller and spiller elements.

Thriller plants demand attention and really make people notice your container. I like to use larger plants for this design element, such as a woody plant or something tropical, but you can also use non-plant elements as the thriller, such as bamboo poles spray-painted a bright color, a repurposed piece of wrought-iron garden art, or any other favorite item that might serve as the starring element in your container. There is a “golden rule” in container design that says that the thriller should be approximately two times the height of your container for maximum impact. So if you have a two-foot-tall pot, your thriller should extend four feet above the top of the container.


  • Abutilon
  • Eucalyptus
  • Found objects
  • Gaura
  • Nicotiana
  • Ornamental grasses
  • Papyrus
  • Tropical plants
  • Woody plants
  • Yucca

Spillers cascade down the sides of the container and provide the base element of interest. The best containers will look like there is a waterfall of plants gushing over the edge and splashing toward the ground. Spillers are planted at the pot’s edge so they can get started growing over the sides immediately. Spillers also soften the edges of a pot and help make the entire container just look huggable.


  • Angel wing begonia
  • Bacopa
  • Ipomea
  • Lantana
  • Lotus
  • Lysimachia
  • Portulaca
  • Scaevola
  • Thyme
  • Verbena

Fillers are the supporting cast and are used to accentuate the rest of the container choices. They literally fill the space between the top of the pot and the lower edge of the thriller design element. Fillers should not take away from the thriller, but help it shine. Consider a variety of sizes when choosing fillers so you have multiple layers of interest in the container. Choosing one plant variety that is one-third the size of the thriller and one that is two-thirds the size of the thriller adds even more variety.


  • Ageratum
  • Cuphea
  • Ferns
  • Geranium
  • Gomphrena
  • Nemesia
  • Osteospermum
  • Pentas
  • Salvia
  • Zinnia

Making these choices is fun and rewarding. As the container grows in over the course of a season, you can always edit as needed to keep the container looking its best. Fillers growing too fast and overtaking your thriller? Just snip them back a bit to reduce their size. Fast-growing spillers overtaking your fillers? Either snip them back or move their trailing growth to a different part of the container that hasn’t filled in as fast. Have you packed too many plants into the container? Surgically remove one or two of the fillers by carefully digging them out, then adjust the remaining foliage to make it look like nothing ever happened. Plant the extracted fillers in a different container or elsewhere in the garden.

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Excerpted with permission fromPractical Organic Gardening, by Mark Highland. Published by Cool Springs Press, © 2017.

Mother Earth Gardener
Mother Earth Gardener
Expert advice on all aspects of growing.