A successful way to pot up flowering containers is to use the thriller-filler-spiller technique. This design approach uses three different types of plants to create a tiered, full display. The central thriller plant, in the middle of the pot, is the focal point. It is the tallest plant and adds a vertical element to the mix. It provides the drama. The thriller can be a flowering or foliage plant, or even an ornamental grass such as purple fountain grass. Plant this one up first in the planter. The next are the filler plants. They surround the thriller and add a rounded appearance to the pot. For this reason, choose plants that have a mounded growth habit. You can use several different plants and interplant them around the thriller. I like to use foliage and annual flowers for this. A few annuals to consider include Diamond Frost® euphorbia, petunia, heliotrope, and lantana.
The last to be planted are the spillers. These are trailing plants that hang over the edge of the planter. These spread and soften the look of the planter. They can also unify the planting if you choose flowers that echo the colors of the other plants. Or you can use trailing plants with unusual textured leaves to add interest to the overall scheme. Some examples are trailing bacopa (Sutera cordata), sweet potato vine, golden creeping Jenny, licorice plant, and variegated ivy.
The thriller-filler-spiller technique is a surefire way to create gorgeous planters. You can vary the height of the central thriller and use tall canna lilies to dominate the scene. Or you can go for the shorter angelonia that almost blends in with the rest.
A tall Lily of the Nile, ‘Glen Avon’ (Agapanthus praecox ‘Glen Avon’) steals the show as the thriller in this outstanding planter. Its sturdy stems hold rounded flower heads consisting of pale blue flowers with a violet stripe along each petal. It is a perennial in zones 8–11. Blooms from July to September. Below it is the filler plant, Diamond Frost® euphorbia. A purple calibrachoa and yellow creeping Jenny (Lysimachia nummularia ‘Aurea’) are the glorious spiller plants. Created by Michael’s Garden Gate Nursery, Mount Kisco, New York.
The upright habit of growth of ‘Serena Lavender’ angelonia (known also as summer snapdragon) makes it perfect as the center thriller in this low-growing thriller-filler-spiller container combination. It has beautiful spikes of 16 inches tall, lavender pea-like flowers with dark eyes from late spring to late summer. Needs sun. It is surrounded by petunias, calibrachoas, and the bicolor blooms of ‘BeBop Pink’ verbena. By Michael’s Garden Gate Nursery, Mount Kisco, New York.
A striking, tall princess flower (Tibouchina urvilleana) adds a tropical touch to a planter. It is an evergreen shrub that is hardy in zones 10–11, so many gardeners use this as an annual (unless they can take it indoors to overwinter). The deep purple flowers bloom throughout summer in partial to full sun. The filler and spillers are annual flowers—white Diamond Frost® euphorbia and blue ‘Crystal Palace’ lobelia. By Michael’s Garden Gate Nursery, Mount Kisco, New York.