Creating a rock garden in an outdoor plant box is a fantastic way to add texture and visual interest to your space while keeping maintenance low. The key is selecting plants that thrive in well-draining soil and can withstand dry conditions. Here are some top choices:

1. Sedum (Stonecrop): These drought-tolerant succulents come in various colors and forms, perfect for filling gaps between rocks.

2. Sempervivum (Hens and Chicks): Hardy and low-growing, they spread easily and add a unique rosette shape to your arrangement.

3. Thyme (Creeping Varieties): Fragrant and resilient, creeping thyme forms a lovely ground cover with tiny flowers.

4. Aubrieta (Rock Cress): A vibrant alpine plant that blooms in spring, cascading beautifully over edges.

5. Dianthus (Pinks): Compact and colorful, these perennials thrive in rocky, dry conditions.

For best results, use a gritty soil mix and ensure your plant box has drainage holes. Pair these plants with decorative stones or gravel to enhance the rock garden aesthetic. With minimal care, your outdoor plant box will become a striking focal point year-round!