Plant Containers

With thrillers, spillers, and fillers.

An elegant planter overflowing with graceful flowers and trailing foliage is a welcome sight by the front door. Putting one together is another matter. The choices can be daunting when trying to decide among the vast array of plants to complement each other. But novices take heart: The thriller-spiller-filler method of choosing plants offers a great guideline for creating abundant, harmonious containers.

Thrillers are your focus plants. They are generally the dramatic or tallest ones, or the dazzlers you just can’t resist. Usually they are planted in the center of the container, but if you prefer a layered look, place them toward the back or on the side. Thrillers draw attention and create height. Snapdragons, tall blue salvias, tropical bananas, and stately palms are all captivating thrillers. Annual geraniums are sturdy, reliable, and colorful.

Spillers drape and cascade over the edges of the container. Variegated vinca vine used to be the most popular spiller, but the options are growing. Calibrachoas are a fantastic spiller loaded with sweet, bell-like flowers (the Proven Winners plant company calls them ‘Million Bells’). Available in more than fifty hues, they happily bloom all summer long. Delicate lantanas, hardy ‘Wave’ petunias, and periwinkle scavola are also popular, colorful spillers with no dreaded deadheading necessary. The licorice plant and its extended family offer a fuzzy, silver, textured leaf that cascades without flowering. With or without flowers, plant your spiller along the container’s edges, where it will drape gracefully and provide extra dimension.

Fillers are the plants that add body, color, and more texture. Don’t underestimate the importance of fillers for setting the tone of the entire container. Let these plants contrast or match the colors and textures of your thriller. Two great filler plants include the dark-leaved ‘Breathless Blush’ euphorbia, and the long-blooming lobularia, a white alyssum-like plant with a long flowering habit, even in hot sun. These are both airy, wobbly in the wind, and prolific growers. The new sun-loving ‘Techno Blue’ lobelia comes in blue, purple, and white, and its brilliant color will jump-start a container. Although perennials have a shorter bloom time, they can provide a different texture and foliage accent. For example, heucheras come in more than three hundred varieties, with names like ‘Plum Pudding’, ‘Lime Marmalade’, and ‘Georgia Peach’ – and their foliage combinations are delicious.

Choosing the right plants

Not all plants get along. One key aspect of combining thrillers, spillers, and fillers in one planter is to remember their individual needs. Some plants like a hot, dry, and sunny spot, while others prefer a cool, moist, and shady environment. Generally it’s the sun and shade aspect of combining plants that is critical. Shade-loving plants can burn in the sun, and sun-loving plants won’t bloom as prolifically in the shade or may simply die.

Michael Faraca, a longtime professional gardener from West Tisbury, uses the thriller-spiller-filler method for all his containers and he likes to mix it up from year to year: “Try something new and different. There are so many choices out there. Give up the old and go to the new.”

The easiest way to choose plants is to try them on for size, like an outfit, mixing and matching, Mike explains. At the garden center, take your thriller, spiller, and filler plants for a walk, matching them with other plants, looking to complement or contrast your existing combination. Blending plants together is the fun part. Try a color theme like red, white, and blue, or assorted shades of purples.

Keep color choices simple, such as a monochromatic theme, for a soothing effect, or mix contrasting plants and colors to create a more energetic feel. Think about the mood you want to foster and what’s most appealing to you, then go for it.

Seven steps to successful planting

Once you’re home from the garden center with your beautiful new plants in hand, getting them planted is the easy part. Here is a step-by-step guide for the beginner container gardener.

1. Good drainage is essential. Be sure your container has holes in the bottom, and put some drainage material in the bottom of the pot. Instead of the usual heavy chunks of broken pottery, Styrofoam packing peanuts are a lighter option – and a great way to recycle them. (They can be a bit messy to clean up post-season, however, so putting them in a mesh onion bag is a good way to contain them, while allowing excess water to pass through.)

2. Fill your pot with a lightweight potting soil or a mixture of soil and peat moss. Be sure to keep it light and fluffy, so the plants can root easily.

3. Use hydrogel moisture-retention crystals such as SoilMoist. When wet, these balloon up into a gooey substance like Jell-O, then they slowly release water into the soil. Soak the dry crystals first, and mix a handful of them into the soil before planting. This product is especially good for part-time residents who may be away sporadically throughout the summer; it’ll help keep your plants from dying of thirst.

4. Pay attention to the roots. When taking plants out of their garden-center pots, loosen the root ball or cut off the very bottom of the roots with a sharp knife to give them a fresh start, especially if the roots have become pot-bound and coiled around themselves. A beneficial product for healthy root growth is mycorrhizal fungi, which encourage the root system to grow more vigorously; just add a little to each planting hole and mix into the soil.

5. After placing plants into their holes, fill in with additional potting soil and firmly press the plants into place. Water immediately to get the soil moist throughout the pot.

6. A slow-release fertilizer applied at the outset saves you from having to fertilize weekly. Container plant fertilizer comes in pellets that can be scattered on top of the soil, or in little sticks that are easily pushed into the soil and remain hidden. This easy one-time application will help ensure plants get the nutrients they need.

7. Place your containers where you can enjoy them daily. A convenient location also makes it easier to keep your new plants watered, fed, trimmed, and deadheaded, and they’ll reward you all summer long.