The common mullein, Verbascum thapsus, is a biennial plant recognized by its tall flowering stalk and soft, woolly leaves. This guide focuses on the delicate yellow flowers, traditionally harvested for their properties. They are primarily used to prepare an infused oil for external applications like ear health. Careful collection and preservation are necessary to retain their subtle constituents.
Identifying the Optimal Time for Harvest
Harvesting typically occurs during the summer months, starting in mid-July, when the plant is in its second year and the main stalk is in bloom. Since mullein flowers open sequentially, only a few blossoms are ready each day. This requires multiple visits over several weeks for a substantial harvest.
To ensure maximum potency, pick flowers once the morning dew has fully dried, typically mid-morning. Harvesting wet flowers introduces excess moisture, which leads to mold development during drying. Select a location away from high-traffic roads or industrial areas to minimize pollutant absorption.
Step-by-Step Harvesting Technique
Collecting mullein flowers demands patience and gentle handling because the individual blooms are small and fragile. Pick only the fully open, fresh yellow flowers, leaving closed buds for subsequent days. Use a basket or paper bag for collection, as plastic containers trap moisture and heat, causing petals to sweat and degrade quickly.
Use your fingers to gently pluck the entire flower, which includes the five yellow petals and the tiny green calyx at the base. Since the plant blooms from the bottom upward, you must leave a significant number of flowers untouched to allow the plant to complete its reproductive cycle and produce seeds. Taking only a portion of the available flowers ensures ethical foraging. Avoid crushing the petals by lightly placing them into the collection container; never pack them down, as bruising releases moisture and hastens decay.
Immediate Post-Harvest Processing and Storage
Flowers must be processed immediately after harvesting, as they are moisture-rich and highly susceptible to mold.
Drying Methods
##### Air Drying
The most effective preservation method is air drying in a thin, single layer on a clean screen, paper towel, or drying rack to maximize air circulation. Place them in a warm, dark, and well-ventilated area, away from direct sunlight, which degrades their color and therapeutic compounds.
##### Dehydrator Use
If using a food dehydrator, set the temperature to the lowest possible setting (95 to 100 degrees Fahrenheit) to gently remove moisture without cooking the petals. Flowers are completely dry when they are papery and brittle, which usually takes a few days depending on ambient humidity.
Storage
Once thoroughly dry, store the flowers in airtight glass containers in a cool, dark location to protect them from light and heat. Properly stored mullein flowers maintain potency for several months, though quality diminishes once the color starts to fade.