If you have an outdoor plant box with poor drainage, selecting the right plants is crucial to ensure they thrive despite soggy soil conditions. Here are some of the best water-tolerant and low-maintenance plants that can handle poor drainage:

1. Hostas – These hardy perennials love moist soil and come in a variety of colors and sizes, making them perfect for shaded areas.

2. Ferns – Many fern species, such as the Ostrich Fern or Lady Fern, naturally grow in damp environments and add lush greenery to your plant box.

3. Astilbe – Known for their feathery plumes, Astilbes flourish in wet soil and bring vibrant colors to your garden.

4. Japanese Iris – These stunning flowers thrive in waterlogged conditions and bloom beautifully in late spring to early summer.

5. Ligularia – With large, bold leaves and bright yellow flowers, Ligularia is ideal for areas with consistently moist soil.

For added drainage improvement, consider mixing in organic matter like compost or using raised beds. By choosing these resilient plants, you can create a thriving outdoor plant box even in less-than-ideal conditions.