What are the best plants for shallow concrete outdoor flower boxes?

Shallow concrete flower boxes are a stylish and durable choice for outdoor gardening, but their limited depth requires careful plant selection. The best plants for these conditions are those with shallow root systems and adaptability to confined spaces. Drought-tolerant succulents like sedum, sempervivum, and echeveria thrive in shallow concrete planters, requiring minimal water and maintenance. Herbs such as thyme, oregano, and creeping rosemary also perform well, offering both beauty and utility. For seasonal color, consider shallow-rooted annuals like petunias, marigolds, or alyssum. Ornamental grasses like blue fescue add texture while staying compact. Always ensure proper drainage and use a well-draining soil mix to prevent waterlogging in concrete containers. These plant choices combine practicality with visual appeal, creating vibrant displays in shallow outdoor flower boxes.