Thrillers are the star
As the name implies, thrillers are the big, attention-getting star players. They are usually tall, upright plants, with outstanding qualities—such as colorful foliage, intriguing shape, or dramatic flowers—that last all season long. Many thrillers are architectural: plants with structural, eye-catching form that can serve as a sturdy backbone or rugged framework for a scrim of less substantial plants. Think of the boldly colorful, paddlelike leaves of Canna ‘Pretoria’ or the bright spikes of Yucca filamentosa ‘Gold Edge’.
Thrillers work best in compositions where they are the tallest plant. For me, they are also the starting point in a container design. I select my thriller, then build around it. At planting time, the thriller goes in the center of a pot that will be viewed from all sides or at the back of a pot that will be displayed in a corner or against a wall.