Garden valerian (Valeriana officinalis), a perennial medicinal herb from Europe and Asia, has been cultivated in North America since the early 19th century. It is valued as an ornamental plant with dark green pointed, toothed leaves with a hairy underside. The thick and hairy stems are hollow and support sweet-smelling white or pale pink flowers that appear between June and July. The flowers are tiny and form tight, dense, umbrella-like clusters. After the bloom, the flowers turn into oblong capsules containing numerous powdery seeds. Those seeds can be a problem: depending on where you are located, valerian can easily become invasive.
|Botanical Name||Valeriana officinalis|
|Common Name||Valerian, Garden valerian, Common valerian, Garden heliotrope, All-heal|
|Mature Size||3 to 5 ft. tall|
|Soil Type||Loamy, sandy, well-drained|
|Soil pH||Acidic, neutral, alkaline|
|Flower Color||White or pale pink|
|Hardiness Zones||4-7 (USDA)|
|Native Area||Europe, Asia|
Garden valerian (Valeriana officinalis) can tolerate both wet and dry conditions enabling it to spread vigorously. Valerian emerges early in the spring, so it often has a head start over native plants that break their dormancy later. Natives might not be able to compete for nutrients, water, and sunlight in a location that valerian has already occupied with its vigorous growth. It's important to be sure that valerian is not allowed to grow unchecked in the typical garden.
If there are just a few valerian plants popping up in your yard, remove them by hand. This is best done by lifting them out of the ground with a trowel to make sure you get the entire plant—the stem breaks easily—as well as the roots. Do this as soon as the seedlings emerge, and definitely before they flower and set seed.
If valerian has overgrown a larger area, you can mow it. Again, this needs to be done before the plants go to seed. If you are too late, mowing or any other form of mechanical removal will make it worse because you will just spread the seeds around further.
A heavy infestation might require repeated mowing and a follow-up spray treatment with an herbicide containing glyphosate. Keep in mind, however, that this is a non-selective herbicide that can kill all other vegetation around it.
Full sun works well for valerian, but some afternoon shade can help this plant thrive.
Valerian prefers sandy or loamy soil. The soil must have excellent drainage for the plant to thrive. Clay soil can be amended with compost to make it more agreeable to valerian.
Consistent, light moisture is necessary for this plant to grow well. Watch the weather and give it a brief watering on days when there will be no rain.
Temperature and Humidity
This is a very cold hardy plant, and it can withstand high temperatures as well. Expect it to die back in freezing temperatures but grow back vigorously at the first sign of spring.
Valerian doesn't need regular feeding. If you do choose to fertilize it, opt for a fertilizer heavy on nitrogen.
Types of Valerian
Red valerian (Valeriana rubra) is a native of the Mediterranean, both northern Africa and southern Europe. It can also be an invasive plant. It blooms in May, earlier than garden valerian. Its star-shaped flowers are crimson-colored, pink, or white. Just like garden valerian, it also self-seeds easily.
Besides the invasive non-native valerian, there are several native species. They usually grow in the wild and are rarely available commercially. These include:
- Mountain valerian, marsh valerian (Valeriana uliginosa)
- Sharpleaf valerian (Valeriana acutiloba)
- Marsh valerian, wood valerian (Valeriana dioica)
- Large-flowered valerian (Valeriana pauciflora)
- Edible valerian or hairy valerian (Valeriana edulis var. ciliata)
These native plants are often rare or threatened species and their removal from the wild is prohibited.
Though valerian doesn't need regular pruning, deadheading the flowers can help prevent the spread of seeds, and thus keep the plant more contained in the garden.
Valerian can be easily propagated through division and seeds. When dividing the plants, carefully tease apart the roots and plant them in new areas of the garden immediately after dividing. Do this in the spring, so the plants have time to become established before winter hits.
How to Grow Valerian From Seed
Valerian is a prolific self-seeder. Its seeds are powdery and spread easily by the wind. In a garden setting, the spreading seeds can be very difficult to control due to their powder-like consistency. To help keep control, deadhead the flowers, and place the flower heads where you want the new valerian to grow. Plant them just under the surface and expect germination in two or three weeks.
Valerian needs no help with surviving the winter. The plant will die back after the first hard frost but will come back vigorously with warmer weather.
Common Pests and Plant Diseases
Valerian is quite hardy and resists most diseases, though root rot is possible if the plant is in soil that doesn't drain well. Aphids occasionally bother this plant but are easily remedied with a blast of water or the use of a mild insecticide.
Can valerian grow indoors?
Valerian is a fast-spreading plant that needs outdoor soil to truly thrive.
What is valerian used for?
The pulverized roots are used as an herbal sedative remedy to treat insomnia, anxiety, and restlessness.
Why do the roots of my valerian plant smell strange?
The outstanding characteristic of the roots is their pungent smell. It is somewhere between earthy and foul and funky, often compared to the odor of dirty socks. That smell persists when valerian root is dried and ground as an herbal remedy.