Siberian Wallflower, Shasta Daisy, Sweet William, purple Coneflower, California Poppy, Candytuft, Blue Flax, Wild Lupine, Common Agrimony, Hound's Tongue, White Clover

So in gardening terms, "perennial" distinguishes a category of plants from annuals or biennials based on their multi-year life cycles and returning growth habit driven by persistent root systems. This makes perennials good long-term investments in ornamental and landscaping gardens.