Creating a Gothic-themed outdoor plant box is all about embracing dark, dramatic, and mysterious aesthetics. Here are the best plants to achieve that enchanting look:

1. Black Mondo Grass (Ophiopogon planiscapus 'Nigrescens') – With its deep black blades, this grass adds a striking contrast and eerie elegance.

2. Coleus 'Black Prince' – This plant boasts rich, dark purple leaves with serrated edges, perfect for a Gothic vibe.

3. Heuchera 'Obsidian' – Known for its glossy, near-black foliage, it thrives in partial shade and adds depth to your arrangement.

4. Dusty Miller (Senecio cineraria) – Its silvery-gray leaves provide a ghostly contrast against darker plants.

5. Bat Flower (Tacca chantrieri) – A rare choice with unique black blooms resembling bat wings, ideal for a hauntingly beautiful display.

Pair these with trailing ivy or ferns for added texture. Choose shade-loving varieties to maintain their dark hues and ensure they thrive in your plant box. A Gothic-themed garden is all about mystery and allure—let these plants set the tone.