The common mullein, Verbascum thapsus, is a biennial plant recognized by its tall flower stalks and large, soft, woolly leaves. Native to Europe, Asia, and northern Africa, it is now widespread globally, including North America. The plant has a long history in traditional practices, primarily for respiratory health and as an infused oil for ear discomfort. Mullein contains beneficial compounds like mucilage, saponins, and flavonoids, which contribute to its traditional use as an expectorant and demulcent. Correct processing is necessary to preserve these compounds, ensuring the material is suitable for internal consumption or topical applications.
Harvesting Mullein Plant Parts
The potency of mullein material depends significantly on the timing of the harvest. Leaves are the most frequently used part for teas and tinctures due to their mucilaginous content. For maximum concentration of beneficial properties, gather the leaves during the plant’s first year of growth when they form a dense, low-lying rosette. Harvesting the leaves before the tall flower stalk appears in the second year is generally recommended for the highest quality product.
The soft, yellow flowers are highly valued for making infused oils and should be collected when they are fully open, usually during mid-summer. Since only a few flowers bloom daily, gathering them requires frequent visits. Roots are sometimes processed for tinctures and should be dug up in the fall of the first year when the plant’s energy reserves are concentrated underground.
Harvest all plant parts on a dry day, after any dew has evaporated, to prevent moisture-related spoilage during drying. It is important to select mullein growing in clean soil, as the plant is a bioaccumulator that can absorb heavy metals. When harvesting, take only a few leaves from each plant’s rosette to ensure continued growth, and avoid any yellowed or damaged foliage.
Proper Drying and Curing Methods
Drying is a necessary step to reduce water content, which preserves the plant’s active compounds and prevents mold growth. Air drying is an effective technique, requiring a well-ventilated space away from direct sunlight, which can degrade delicate compounds.
The leaves and flowers require different drying approaches. Mullein leaves are thick and woolly, making them susceptible to moisture retention, so they should be laid out in a single layer on screens or paper towels. If using a dehydrator, a low temperature setting (approximately 95 to 100 degrees Fahrenheit) is recommended. The more delicate flowers are spread in a thin layer and dry more quickly than the leaves. The material is fully dried once it becomes brittle and easily crumbles. After drying, the material should be allowed to “cure” by resting in a container with a loose lid for a few days to equalize any remaining internal moisture before final storage.
Preparing Mullein for Consumption and Topical Use
Once the mullein is fully dried, it can be converted into several usable forms, with infusions and infused oils being the most popular. To create a simple tea for respiratory support, steep approximately one to two teaspoons of dried mullein leaf or flower in one cup of boiling water for 10 to 15 minutes. For a stronger medicinal infusion, the plant material can be steeped for four to eight hours, or even overnight.
For topical applications, such as ear drops, the flowers are typically infused into a carrier oil like olive oil. This infused oil can be prepared using two primary methods.
Passive Infusion
The dried flowers are submerged in oil in a jar and allowed to sit for several weeks.
Active Infusion
This quicker method involves gently heating the oil and flowers in a double boiler for two to three hours at a low temperature, around 125 to 130 degrees Fahrenheit. This heat-based infusion is often preferred when the oil is needed quickly.
Tinctures offer a highly concentrated form and are created by soaking the dried or fresh material in high-proof alcohol (typically 60 to 90 percent). The plant material macerates in the alcohol for an extended period, often a month or more, before the liquid is strained. Proper ratio of plant material to solvent maximizes the extraction of beneficial compounds.
Storing Processed Mullein and Safety Considerations
Proper storage is necessary to maintain the potency of the processed mullein over time. Dried leaves and flowers should be stored in airtight containers, such as glass jars, to protect them from moisture and oxygen. Keep the containers in a cool, dark location away from direct light, which can cause active compounds to degrade. When stored correctly, dried mullein material can retain its quality for up to a year.
All preparations of mullein require careful attention to straining due to the plant’s unique structure. Mullein leaves and stems are covered in fine, hair-like appendages called trichomes, which can cause irritation if ingested. For teas and infusions, the liquid must be strained through a very fine filter, such as a coffee filter or cheesecloth, to remove these microscopic hairs. Failing to filter the preparation can result in throat irritation.
Similarly, any infused oil, especially those intended for ear use, must be thoroughly strained to ensure no plant matter remains. The final processed oils and tinctures should be stored in dark glass bottles to protect them from light and preserve their efficacy. It is also important to note that mullein oil should never be used in the ear if a ruptured eardrum is suspected.