Veronica serpyllifolia earns its common name honestly: its small, rounded leaves do resemble thyme, forming low mats that spread steadily across garden beds and open ground. Part of the plantain family, this perennial blooms in spring with the characteristic small blue flowers that define the speedwells, appearing on short upright stems before the season heats up. Hardy from zones 3 through 8, it tolerates cold winters and returns reliably without any fuss.

Given well-drained soil and a spot in full sun to partial shade, thymeleaf speedwell establishes without difficulty. It can be grown from seed or division, and dividing clumps every few seasons in fall keeps the plants vigorous and prevents them from becoming ragged at the center. It suits rock gardens, path edges, and anywhere a fine-textured, spreading perennial is called for.