Stark, simple lines and structural shapes create high drama. One large plant placed in a geometric-shaped container is visually appealing. Consider location for maximum benefit. A plant next to a wall will likely cast a shadow, which may be an added perk. Mexican fence post cactus (Pachycereus marginatus) and New Zealand flax are plants that are easy to care for.
While your yard may not be suitable as a prairie, there's nothing stopping you from creating a lookalike. Containers in various sizes and of a natural hue create a base. Consider the effects of wind. Tall plants that sway in the breeze can be placed in the back, while smaller, more textural plants can sit in front. Wild rye grass (Leymus triticoides) and red bunny tails (Pennisetum messiacum) are suitable choices.
Repurposed containers or simple pots will suffice in the eclectic garden. Teacups planted with succulents or a simple array of planters attached to a fence conveys relaxed fun. The top of a birdhouse can be a stolen spot for greenery such as sedum.