Chamomile is a fragrant herb valued globally for its use in herbal teas and aromatherapy. It is represented by two main species. The most common variety cultivated for its flowers is German chamomile (Matricaria recutita), which is an annual plant that easily reseeds itself. Roman chamomile (Chamaemelum nobile) is the other species, generally a perennial used as a groundcover, but commercial seeds usually belong to the German variety.
Detailed Physical Characteristics
Chamomile seeds are technically classified as achenes, which are small, dry, single-seeded fruits that do not split open at maturity. These achenes are extremely tiny, often described as dust-like, making them difficult to handle. A thousand German chamomile achenes weigh only between 0.088 and 0.153 grams.
The achenes are oblongoid structures, meaning they are slightly tapered or nearly cylindrical in shape. Their color is typically a pale yellowish-brown or ivory, blending in with dried plant material. A distinguishing feature is the presence of several fine, subtle longitudinal ribs or striations running along the surface, which can sometimes be seen under magnification.
Where Seeds Are Located on the Plant
Achenes develop from the tiny yellow disk florets that make up the central dome of the characteristic daisy-like flower head. They form directly on the receptacle, which is the central structure beneath the petals. In German chamomile, this receptacle is characteristically hollow and becomes distinctly conical or cone-shaped as the flower matures and the achenes ripen.
To collect the achenes, one must wait until the white ray petals have dropped and the central yellow dome turns a brownish color. At this point, the entire flower head is dried, and the mature achenes can be easily shaken or rubbed off the cone-shaped receptacle. These ripe achenes are designed to fall off the plant to self-sow, which is why they are often found loose within the dried flower material.
Practical Considerations for Sowing
Due to their minuscule size, chamomile achenes have specific requirements for successful germination. They require light to sprout, a characteristic known as being photoblastic. This means the achenes must not be covered with soil, as burying them will prevent germination.
Instead, the achenes should be surface-sown by pressing them gently onto the top of moist soil. To ensure a more even distribution, gardeners often mix the achenes with a small amount of fine sand or inert material before scattering them. Consistent moisture must be maintained through misting, and the optimal soil temperature for germination ranges from 65°F to 85°F.