Creating a porcupine-resistant outdoor plant box requires selecting plants that are unappealing or even deterrent to these curious critters. Porcupines are known for their love of tender greens, bark, and fruits, but certain hardy, spiny, or strongly scented plants can help keep them at bay.

1. Rosemary (Rosmarinus officinalis): This aromatic herb is not only a culinary favorite but also a natural porcupine repellent due to its strong scent and tough, needle-like leaves.

2. Lavender (Lavandula): With its fragrant blooms and woody stems, lavender is rarely bothered by porcupines, making it a beautiful and practical choice.

3. Barberry (Berberis): The thorny branches of barberry shrubs act as a physical barrier, discouraging porcupines from nibbling.

4. Yucca (Yucca spp.): Its sharp, sword-like leaves and bitter taste make yucca an excellent porcupine-resistant option.

5. Boxwood (Buxus): While not entirely immune, boxwood’s dense foliage and bitter flavor are less appealing to porcupines compared to softer plants.

For added protection, consider elevating your plant box or using wire mesh around vulnerable areas. Combining these plants with other deterrents, like motion-activated sprinklers, can further safeguard your garden. By choosing the right plants, you can enjoy a lush, porcupine-free outdoor space.