Oregano is a culinary herb often started directly from tiny seeds. Identifying these seedlings correctly is important for successful cultivation, as understanding the distinct stages of early growth prevents accidentally removing the herb while weeding. The process begins with the emergence of the first embryonic leaves, which bear little resemblance to the mature foliage.
The First Stage: Cotyledon Leaves
The initial pair of leaves to emerge are the cotyledons, which develop at the top of a thin, delicate stem typically measuring one to two inches in height. These seed leaves are generally rounded or teardrop-shaped and are much smaller than the subsequent true leaves. They are usually a smooth, light green color, though sometimes a faint purple hue may be present on the edges.
Cotyledons serve as the primary food source until the first true leaves can begin photosynthesis. Their structure is simple, lacking the texture and complex veining of mature foliage. They are arranged directly opposite each other on the stem, but this uniform appearance is characteristic of many seedlings and is not distinct enough for positive identification.
Identifying the True Oregano Leaves
The defining features of the oregano seedling appear with the development of the true leaves, which grow directly above the cotyledons. These leaves are the first to resemble the mature plant’s foliage and are oval-shaped with slightly toothed or entire edges. They transition from the light green of the cotyledons to a deeper, more saturated green color.
A distinguishing characteristic is the development of a fine layer of fuzz or hairiness, giving the leaf a slightly coarse texture. The true leaves maintain the opposite arrangement, growing in pairs across from one another along the stem. The most reliable identifier at this stage is the distinctive, pungent oregano aroma that is released when a true leaf is gently rubbed.
Comparing Oregano Seedlings to Common Weeds
Differentiating oregano from common garden weeds requires checking for the features that develop after the cotyledons have emerged. The unique, strong scent of oregano is absent in nearly all weed seedlings, offering a simple field test for confirmation. Oregano belongs to the mint family (Lamiaceae), and this lineage often results in a subtle squareness to the thin stem, a trait less common in many garden weeds.
The true leaves of oregano tend to be oval with soft edges. In contrast, many weed species, particularly those in the mustard family, develop deeply lobed or serrated leaves very early on. If the seedling appears randomly outside of where seeds were intentionally sown, or if it lacks the opposite leaf arrangement and the characteristic aroma, it is likely an unwanted plant.