The toothache plant, scientifically known as Acmella oleracea, is a fascinating herb cultivated for its unique ornamental qualities and traditional medicinal uses. It is often called Spilanthes, Paracress, or Electric Daisy due to the intense, tingling sensation its leaves and flower buds produce when chewed. Originating from the tropics of Brazil, it has a long history of use in indigenous communities for its numbing properties. It produces distinctive, cone-shaped, yellow and red flowers that resemble small eyeballs, earning it the nickname ‘Eyeball Plant’. The ability of this herb to produce a strong tingling sensation, which transitions into a mild numbness, makes it a popular addition to gardens.
Starting Toothache Plant From Seed or Cutting
Propagating the toothache plant can be achieved through either tiny seeds or readily rooting stem cuttings. Starting seeds indoors is the most common approach, done about six to eight weeks before the last expected frost date. The seeds require warmth, ideally a soil temperature between 70°F and 85°F, and light to germinate. Therefore, they should be gently pressed onto the surface of a well-draining seed-starting mix rather than buried.
Germination typically occurs within one to two weeks, provided the soil remains consistently moist and warm. Once the danger of frost has passed and nighttime temperatures are reliably above 55°F, the seedlings can be transplanted outdoors. Seedlings should be spaced approximately 10 to 12 inches apart to allow for the plant’s natural sprawling growth habit.
Alternatively, the plant roots easily from cuttings taken from healthy stems. A cutting should have the lower leaves removed and can be placed directly into moist soil or a glass of water until roots begin to form. This method offers a faster way to establish a mature plant.
Ideal Growing Conditions
The toothache plant thrives in warm conditions and is considered a tender annual in most temperate climates, succumbing quickly to frost. It performs best when planted in a location that receives full sun, meaning at least six to eight hours of direct sunlight each day. Although it can tolerate partial shade, less sun will result in fewer of the prized flower buds.
For optimal growth, the plant requires a loose, fertile, and well-draining soil composition, ideally amended with organic matter like compost. Poor drainage can quickly lead to root rot, so a loamy soil mixture is recommended for adequate aeration. The plant prefers a slightly acidic to neutral soil pH, with an optimal range generally falling between 6.0 and 7.0.
If growing in a container, select a pot that is at least 2.5 to 5 gallons in size to accommodate the plant’s extensive root system. Choosing a container with ample width is often more beneficial than one with extreme depth, as this better suits the plant’s growth pattern.
Ongoing Care and Pruning
Consistent moisture is necessary for the toothache plant to flourish, as it does not tolerate drying out for extended periods. The soil should be kept evenly moist, but not waterlogged, with watering done when the top one to two inches of soil feel dry to the touch. Watering at the base of the plant is preferable to wetting the foliage, as moist leaves can encourage fungal diseases.
The plant benefits from moderate feeding throughout the growing season to support its continuous production of leaves and flowers. A balanced, all-purpose fertilizer can be applied every four to six weeks, particularly for plants grown in containers where nutrients leach out more quickly. Avoid excessive nitrogen, which promotes leafy growth rather than flower production.
Regular pruning helps maintain a dense, bushy shape and prevents the stems from becoming long and spindly. Pinching back the stem tips encourages the plant to branch out, which increases the overall yield of leaves and flowers. The toothache plant can occasionally be bothered by common garden pests like aphids and whiteflies, which can be managed with insecticidal soap or a strong jet of water.
Harvesting and Usage
Harvesting the toothache plant can begin once the plant is well-established, usually around 90 days after planting, when it is in full bloom and the flower buds are mature. Both the leaves and the distinctive, cone-shaped flower buds are used, but the buds contain the highest concentration of the active compounds. To harvest, snip the stems just above a set of leaves, which encourages the plant to branch and produce more growth.
The most notable compound is spilanthol, an alkamide that targets pain-mediating receptors, creating the characteristic tingling sensation that leads to a numbing effect. This sensation is caused by the spilanthol slowing the nerve signal response in the mouth and is often accompanied by increased saliva production.
The harvested leaves and flowers can be used fresh in salads or as a culinary spice, while the flowers are often chewed directly for their numbing effect. For long-term use, the plant material can be dried on screens with good air circulation or processed into a tincture using alcohol. Drying should be done quickly in a shaded, well-ventilated area to preserve the active compounds.