Solstitial nastic movements, the rhythmic responses of plants to seasonal changes in daylight, are a fascinating phenomenon for gardening enthusiasts. If you're looking to showcase these movements in outdoor plant boxes, certain plants stand out for their dramatic and observable behaviors.

1. Sunflower (Helianthus annuus)

Sunflowers are iconic for their heliotropic movements, tracking the sun from east to west during the day. While not strictly solstitial, their responsiveness to light makes them a great addition to demonstrate nastic movements.

2. Morning Glory (Ipomoea purpurea)

Morning glories exhibit phototropic responses, opening their blooms at dawn and closing them by afternoon. Their sensitivity to light changes makes them ideal for observing solstitial patterns.

3. Sensitive Plant (Mimosa pudica)

Though more known for thigmonasty (touch response), Mimosa pudica also shows subtle light-dependent movements, making it an intriguing choice for plant boxes.

4. Oxalis (Oxalis triangularis)

Oxalis leaves open and close in response to light intensity, a clear example of nastic movement. Their striking foliage adds visual appeal to outdoor setups.

5. Dandelion (Taraxacum officinale)

Dandelions close their flowers in the evening and reopen them in the morning, a simple yet effective demonstration of solstitial rhythms.

For optimal results, position your plant boxes in areas with consistent sunlight exposure. Regular watering and well-draining soil will ensure healthy growth, allowing these plants to fully express their unique movements. Observing these behaviors not only enhances your garden's beauty but also deepens your appreciation for plant adaptability.