Valerian (Valeriana officinalis) is a tall, old-fashioned perennial herb in the Caprifoliaceae family, grown less for its foliage than for its thick, gnarled root, long used as an herbal sleep aid. It's native to Europe and parts of Asia but has naturalized widely across North America, including along roadsides and pasture edges here in Kentucky, which says something about how little fuss it needs. In the garden it behaves as an easygoing cottage-garden perennial, a clump of ferny foliage that sends up tall, airy flower stems topped with clusters of small, sweetly fragrant white-to-pink blooms in early summer. Valerian is simple to grow and largely untroubled by pests, making it a good choice whether or not you ever dig the root; the main patience required is waiting out a full second year before that root is worth harvesting.
Sowing and planting
Valerian can be started from seed or bought as a potted plant, and either route works well in zone 6b. Seed germinates best with light, so press it onto the surface of the mix rather than burying it. Start indoors 6 to 8 weeks before the last frost, or direct-sow outdoors in spring once the soil is workable; germination can be slow and uneven, often taking 2 to 4 weeks, so don't give up on a tray too early.
Transplant or thin seedlings to 18 inches (45 cm) apart once they carry a few true leaves, choosing a spot in full sun to part shade with average, well-drained soil. Valerian isn't fussy about fertility and tolerates a range of pH, but young plants do better with consistent moisture while they establish their root systems. Fall planting of nursery starts also works well in zone 6b, giving roots a head start before the following year's main growth.
Growing on
Water young plants regularly through their first season, then ease back; established valerian handles average garden moisture well and doesn't need supplemental watering except during extended dry spells. The plant isn't a heavy feeder — a layer of compost worked in at planting time and a light top-dressing each spring is enough to keep it productive without pushing soft, floppy growth.
By its second year, valerian sends up flower stalks that can reach 4 to 5 feet (120 to 150 cm), and these airy stems may need a stake or a discreet grow-through support in an exposed spot, especially after summer rain weighs the flower heads down. The sweetly fragrant blooms draw bees, butterflies, and other pollinators through early summer, which makes valerian worth growing as an ornamental on its own, even where the root is never dug.
The one piece of maintenance worth staying on top of is deadheading. Valerian self-seeds freely, and a stand left to go to seed can spread well beyond where it was planted, turning up in paths, beds, and lawn edges the following year. Cut spent flower stalks back before seed sets if you want to keep the planting contained; if a drift of valerian spreading through a cottage-garden bed doesn't bother you, let it go and simply pull unwanted seedlings as they appear.
Harvesting
Valerian isn't picked for continuous cutting the way a culinary herb is; the part most gardeners want is the root, and it isn't worth digging until the plant has had a full season to bulk it up. Most growers wait until fall of the second year, once the plant has flowered and top growth has started to die back, before lifting it. Loosen the soil carefully with a garden fork well away from the crown, then lift the whole root mass by hand; valerian roots are thick, branching, and somewhat brittle, so work slowly to keep as much of the root intact as you can.
Wash the harvested roots well to remove soil, then slice the thicker pieces lengthwise so they dry evenly. Dry them in a single layer in a warm, well-ventilated, shaded spot, or use a dehydrator on a low setting; valerian root has a strong, distinctive odor that grows more pronounced as it dries, so dry it somewhere separate from stored food if the smell bothers you. Once fully dry and brittle, store the root in an airtight container out of direct light, where it keeps its potency for up to a year.
If you'd rather keep the plant going as a garden perennial than dig it for root, you can skip harvesting altogether; valerian is a reliable, long-lived clump that returns on its own each spring and asks for little beyond the occasional deadheading.
Problems and pests
Leaves with ragged holes or skeletonized patches
Valerian is seldom bothered by serious pests, but slugs and snails will chew holes in young foliage, especially in a damp spring. Handpick them in the evening or set out shallow traps; established plants usually outgrow the damage on their own once growth picks up.
Aphids clustered on new growth or flower stems
Aphids occasionally cluster on tender new shoots and the flower stalks as they elongate. A firm jet of water knocks most colonies off, and the ladybugs and other beneficial insects that valerian's flowers help attract usually keep numbers in check without any spray needed.
Plant flopping over or stems snapping in wind
The tall, hollow flower stems are the plant's main structural weak point; after heavy summer rain or a stretch of wind, mature stalks can lean or snap. Stake plants in exposed spots before flowering, or interplant valerian among sturdier neighbors that give the stems some support.
Seedlings coming up where they weren't planted
This isn't a pest or disease, but it catches new growers off guard: valerian self-seeds readily, and a mature stand left unchecked produces volunteer seedlings well beyond the original bed. Deadhead spent flowers before seed sets if you want to keep the planting contained, and pull unwanted seedlings while they're small and easy to identify.
Roots that rot rather than bulk up
In heavy, poorly drained soil, valerian's roots can rot rather than develop into firm, harvestable roots, particularly over a wet winter. Plant in well-drained soil or a raised bed if your garden tends to stay soggy, and avoid overwatering established plants, which tolerate dry spells far better than wet feet.
Varieties worth growing
- Common valerian – The species most gardeners grow and the only one traditionally used for root; sold simply as Valeriana officinalis seed or divisions, since named cultivars are uncommon.
- All-heal – An old common name for the same plant, reflecting its long history in folk herbalism; look for it under this name in older seed-saving and herb-garden references.
- Garden heliotrope – Another traditional common name for Valeriana officinalis, used especially by gardeners growing it as an ornamental rather than for root.
- Red valerian (Centranthus ruber) – A popular, drought-tolerant cottage-garden plant often confused with true valerian because of the shared common name; it is unrelated botanically and not used as an herbal sleep aid, but it's a fine, low-maintenance companion for a similar spot in the border.
- Jacob's ladder (Polemonium caeruleum) – Sometimes sold as "Greek valerian," this is another unrelated plant worth knowing only so you don't buy it by mistake if you're after the true herb.