The Valerian plant (Valeriana officinalis) is a hardy perennial herb sought after for its distinctive root system. This species is a straightforward addition to the home garden when its specific needs are met. Cultivating Valerian from seed or division requires attention to site selection and proper timing to ensure a robust harvest. This guide covers the horticultural methods and routine maintenance necessary for successful growth.
Ideal Growing Conditions and Starting Valerian
Selecting the correct planting location is crucial for successful cultivation. Valerian thrives best in full sunlight (at least six hours daily), but it tolerates partial shade. Too much shade causes the tall flower stalks (up to five feet) to become weak and flop over. As a hardy perennial, Valerian flourishes across USDA hardiness zones 4 through 9.
Valerian prefers fertile, loamy soil that retains moisture but drains well. Good drainage is necessary to prevent the fibrous root system from developing rot. The soil pH should ideally range from slightly acidic to neutral (5.5 to 7.0). Before planting, incorporate generous amounts of organic matter, such as well-rotted compost, to improve soil structure and nutrient content.
Propagation uses seeds or division of mature plants. Seeds require light for germination, so press them lightly onto the soil surface rather than burying them deep. Germination improves if seeds undergo cold stratification, either naturally by sowing in late fall or artificially via refrigeration. Set out transplants or divisions in the spring or fall, spacing them 18 to 40 inches apart to allow for mature clump size.
Essential Ongoing Care and Maintenance
Once established, Valerian requires consistent moisture, especially during the first growing season and dry spells. Keep the soil evenly moist, mimicking its native damp conditions, but avoid water accumulation around the roots. Applying organic mulch around the plant base helps regulate soil temperature and reduce moisture loss through evaporation.
Valerian is a light feeder and does not require extensive fertilization. An initial amendment of compost worked into the soil at planting time is usually sufficient. If the soil is poor, apply a light side-dressing of a balanced, all-purpose fertilizer (e.g., 5-10-10 formulation) once a month during active growth. Avoid over-fertilizing, as excess nitrogen promotes leaf growth at the expense of root development.
Routine care involves managing the plant’s aggressive self-seeding tendency. Valerian produces fragrant white or pink flowers on tall stalks in the summer. Deadheading (cutting off spent flower heads before they set seed) prevents the plant from spreading uncontrollably. This practice also channels the plant’s energy toward developing a robust root system for harvesting.
In late fall or early spring, cut the remaining foliage and flower stems back completely to the ground as the plant enters or emerges from dormancy. Valerian is resistant to most pests, but young plants can be susceptible to damage from slugs and snails, especially in moist conditions. Fungal issues, such as powdery mildew, may appear if air circulation is poor or humidity levels remain high. Adequate spacing and watering the soil directly helps mitigate these problems.
Harvesting and Preparing the Root
The root is the part most valued for harvest, requiring patience until the plant is mature. The optimal time for harvesting is in the autumn of the second year of growth, or in the early spring before new growth begins. Waiting until the second year allows the rhizomes and roots to fully develop and accumulate necessary compounds. To encourage root growth, the plant should be consistently deadheaded during its first two summers.
When harvesting, dig the roots on a day when the soil is slightly moist, which eases excavation. The root system is deep and sprawling, so carefully dig up the entire plant using a garden fork to avoid damaging the fine roots. Once lifted, cut the aerial parts (stems and foliage) away from the root mass.
Thoroughly clean the harvested roots to remove all adhering soil and debris. Because the root system is fibrous and has many small parts, cleaning is often best accomplished by repeatedly rinsing the roots in a bucket of clean water. Once cleaned, chop the roots into smaller, uniform pieces to facilitate the drying process.
Drying must occur in a well-ventilated space, as the roots release a strong, distinctive odor. A shed or outdoor area is preferable to an indoor living space for this reason. Spread the chopped roots in a single layer on a screen or tray and air-dry until they snap cleanly. Alternatively, they may be dried in a low-heat oven (about 200 degrees Fahrenheit) with the door slightly ajar. Store fully dried roots in an airtight container away from direct light to maintain quality.