Osmonasty, the movement of plants in response to osmotic changes, is a fascinating phenomenon that can add dynamic beauty to your outdoor plant boxes. If you're looking to showcase this unique trait, here are some of the best plants to consider:

1. Mimosa pudica (Sensitive Plant): Known for its rapid leaf-folding response to touch or changes in light, this plant is a classic example of osmonasty. Its delicate foliage reacts visibly, making it a standout in any garden box.

2. Oxalis triangularis (Purple Shamrock): This plant's leaves open and close in response to light and humidity, demonstrating a slower but equally captivating osmonastic movement.

3. Dionaea muscipula (Venus Flytrap): While famous for its trapping mechanism, the Venus Flytrap also exhibits osmonasty as its lobes close when triggered by prey or environmental changes.

4. Maranta leuconeura (Prayer Plant): Its leaves fold upward at night, a response to changes in light and humidity, creating a striking visual effect in outdoor plant boxes.

5. Codariocalyx motorius (Telegraph Plant): This lesser-known plant moves its leaves in a jerking motion due to osmotic changes, offering a unique display of osmonasty.

For optimal results, ensure your plant boxes have well-draining soil and consistent moisture to support these plants' osmotic responses. Pairing them with static plants can create a visually engaging contrast, highlighting their movement.

By incorporating these osmonastic plants into your outdoor plant boxes, you’ll not only enjoy their beauty but also witness the wonders of plant biology in action. Happy gardening!