Creating a black hole atom-themed outdoor plant box is a fantastic way to blend cosmic inspiration with gardening. To achieve this striking aesthetic, focus on plants with dark foliage, unusual textures, and a mysterious allure. Here are the top choices:

1. Black Mondo Grass (Ophiopogon planiscapus 'Nigrescens') – Its deep purple-black blades mimic the void of a black hole, adding depth and contrast.

2. Black Coral Elephant Ear (Colocasia 'Black Coral') – Large, dark leaves create a dramatic, otherworldly effect.

3. Obsidian Coral Bells (Heuchera 'Obsidian') – Glossy black foliage with delicate flowers adds elegance.

4. Black Velvet Petunia (Petunia 'Black Velvet') – These velvety, near-black blooms evoke a cosmic vibe.

5. Dark Opal Basil (Ocimum basilicum 'Dark Opal') – Deep purple leaves offer both visual appeal and culinary use.

Pair these with silver or white accent plants like Dusty Miller or Artemisia to simulate stars and cosmic dust. For texture, add succulents like Echeveria 'Black Prince' or Haworthia 'Zebra Plant.'

To enhance the atom theme, arrange plants in circular patterns or use geometric planters. Incorporate LED string lights or glow-in-the-dark pebbles to mimic celestial energy. This unique garden design will transform your outdoor space into a mesmerizing cosmic oasis.