Creeping thyme, Thymus serpyllum, is often grown as an ornamental ground cover, leading many to question its edibility. Creeping thyme is generally safe for consumption, but it possesses a significantly milder and more delicate flavor profile compared to common culinary thyme, Thymus vulgaris. Understanding these differences is helpful for both safety and proper culinary application.
Safety and Edibility of Creeping Thyme
Creeping thyme is an edible herb, and all parts of the plant—stems, leaves, and flowers—are considered non-toxic when consumed in typical culinary quantities. It has a long history of use in traditional medicine and cooking across Europe, and scientific reviews indicate its preparations are generally recognized as safe for food use.
A strong consideration for safety involves the source of the plant, as T. serpyllum is frequently utilized as a fragrant ground cover in gardens and public spaces. Ensure the plant has not been treated with chemical herbicides or pesticides, which is a concern when harvesting from ornamental beds. Pregnant or breastfeeding individuals should avoid consuming large, concentrated doses. Furthermore, individuals with pre-existing thyroid disorders should consult a healthcare professional before consuming it regularly in medicinal amounts, as thyme may affect hormones controlling the thyroid gland.
Flavor Profile and Best Uses
The flavor of creeping thyme is notably different from its robust culinary cousin, presenting a softer and more nuanced aromatic experience. Its essential oils give it a flavor often described as lighter, more floral, or sometimes with a subtle hint of mint or lemon, depending on the specific chemotype. This delicate flavor means it can be easily overpowered by strong ingredients or long cooking times.
Creeping thyme is best utilized in applications where its subtle aroma can shine without being subjected to heat that would destroy its volatile compounds. The fresh leaves and vibrant pink or purple flowers make edible garnishes for salads, cheeses, or plated desserts. It excels when steeped in hot water for a mild herbal tea, or when used to infuse simple syrups, vinegars, or mild sauces. Because its flavor is mild, it can be used more generously than T. vulgaris, but it is not suited for long-simmering stews or heavy meat rubs.
Distinguishing Creeping Thyme from Other Species
Accurate identification of Thymus serpyllum is important, especially if harvesting from the wild or a garden where it may be confused with other low-growing plants. Creeping thyme is identified by its prostrate, mat-forming growth habit, typically standing only 2 to 3 inches high but spreading horizontally. Its stems are thin, somewhat woody, and trail along the ground, often rooting where they touch the soil.
The leaves are small, elliptical, and nearly stalkless, measuring about 1/4 inch in length, which is smaller than many culinary varieties. When it blooms in the summer, the plant produces dense clusters of tiny, tubular, two-lipped flowers that are typically deep pink to purple. This low, spreading form and small foliage distinguish it from the more upright, bushier growth habit of common culinary thyme.
Potency Compared to Culinary Thyme
The difference in flavor between creeping thyme and culinary thyme is rooted in their varying chemical compositions of volatile oils. Creeping thyme contains a lower overall concentration of the aromatic compounds responsible for the pungent flavor. Culinary thyme (T. vulgaris) is valued for its high content of phenols, specifically thymol, which can constitute 35% to over 45% of its essential oil content.
In contrast, the essential oil of T. serpyllum is often lower in overall yield and contains carvacrol as a major component, sometimes reaching 45%, alongside compounds like \(gamma\)-terpinene and p-cymene. While both carvacrol and thymol provide the herb’s aroma and antimicrobial properties, the lower and more varied concentration of these oils in T. serpyllum results in the milder taste. This chemical distinction explains why more creeping thyme is required to achieve the strong aromatic presence characteristic of culinary thyme.