Burdock (Arctium lappa and Arctium minus ) is considered a common biennial weed in much of North America, where nitrogen-rich soils cause it to thrive and spread rather rampantly. Burdock is not highly prized for its appearance. Growing as much as 10 feet tall, it has a frankly weedy appearance, with large floppy leaves. In the first year, the leaves remain close to the ground, then a tall flower stalk shoots up in the second year to produce purple flowers and thistle-like seed burrs.
It is a common plant to see in untended pastures and along roadsides, and it self-seeds readily. The seed pods dry into velcro-like burrs that cling to everything—including your clothing and pet's hair.
But burdock also has a surprising number of culinary and herbal uses. Its roots, sweet but pungent in flavor, are commonly used in cooked dishes or as a flavoring in teas. In Asian cooking, burdock (Gobo root) is commonplace. The immature stalks are also sometimes consumed—they are said to resemble artichoke in flavor. The young leaves can be also used in salads or in cooked dishes.
Burdock is also known as a medicinal food; meaning it nourishes the body and offers deep nutritive health to the body, notably the liver and urinary tract and skin.
In warm climates, burdock can be planted from seed in the fall. In colder climates, it is normally planted in the spring. Burdock is a fast-growing plant that will achieve its full height by end of summer. Harvesting of the roots can begin about 90 days after germination.
|Botanical Name||Arcrtium lappa|
|Common Name||Burdock, greater burdock, common burdock, gobo|
|Size||6–10 feet tall|
|Sun Exposure||Full sun to part shade|
|Soil Type||Sandy, well-drained soil|
|Soil pH||6.6–7.5 (neutral)|
|Hardiness Zones||2–11 (USDA)|
How to Plant Burdock
Burdock can be cultivated as an edible herb in almost any garden soil, where ideal conditions can make it grow quite tall. Be aware that once established, this plant can be hard to eradicate. Burdock has deep tap roots that absorb copious amounts of nutrients from the soil, so it is best planted away from other deep-rooted vegetables, such as potatoes, onions, carrots, and beets. It makes a better companion for asparagus and legumes.
It will grow well in part shade, so burdock is a good choice for areas of a landscape that don't see full sun, such as in the shade of a large tree. Stratification of the seeds before planting will help germination, which can otherwise be erratic. Once plants are established, seeding is not necessary—burdock will self-seed quite readily. For the fewest problems, grow burdock in an area where self-seeding is not a problem. This will ensure endless crops of seeds and roots for years to come.
Burdock will do equally well in full sun or part shade, but it has a preference for some shade.
This plant will do well in almost any soil, but if you want to harvest the roots, sandy loam is best. The roots can extend as much as 3 feet into the ground, and harvesting can be very hard if the soil is dense and packed.
Burdock almost never needs additional watering if your region is getting some regular rainfall. A total of 1 inch every two weeks is perfectly sufficient.
Temperature and Humidity
This plant does well in all temperature and humidity conditions throughout North America.
This is not a plant you should feed, as it becomes almost too vigorous in soils high in nitrogen.
There are two forms of edible burdock commonly grown. In addition to Arctium lappa, sometimes known as greater burdock, common burdock (Actium minum) is a prevalent plant across North America. It can be hard to tell the difference between these plants, but common burdock is slightly smaller, its flowers do not have stalks, and the main stems are hollow rather than solid. Both plants have similar uses.
Young leaves, stalks, and roots of burdock all have culinary and medicinal uses, but the best harvesting occurs early in the season, before the plant has become too large. Young leaves can be clipped from the plant beginning in mid-summer for use in salads or cooking, much the way spinach is used.
If you want to use the roots, wait until the end of the plant' first year (or early in its second year) to dig up the plant and remove the roots. This is best done after moisture has been applied to the soil, as burdock has a very deep, large taproot. This taproot needs to be dug out with a spade or garden fork. Do not attempt to pull the root, as it will usually break off partway down the root, and you will be left with a stub. The roots can be used in many recipes—boiled, roasted, or fried. Wash the roots very well to remove all loose dirt or sand before drying. The roots also need to be chopped or sliced before drying, as they become rock hard once dry.
The seeds are generally harvested at the end of the second year, at the point where the seed pods form burrs with velcro-like hooks. Seeds should be removed from their prickly outer coating and then dried before storage. Look them over well for hidden insects. The seeds are often used in folk remedies as a pain reliever for ailments such as toothache and arthritis.
Herbalists have a wide range of uses for burdock, though medicinal uses should be supervised. Burdock can be used for skin issues, both from within and applied directly to the surface of the skin. Fresh burdock leaves (either first or second year) can be lightly steamed and then applied as a poultice to draw out infection and speed healing. Burdock seed tincture should not be used by the home herbalist due to its strong efficacy. Tinctures are not safe to ingest while pregnant, or for those with certain medical issues, so consult with a doctor before using.
Once a patch of burdock is established, it's somewhat rare to intentionally propagate it, since the plant self-seeds so readily. If you do want to share plants or create additional burdocks, collect the seeds from the burrs, which ripen at the end of the plant's second year. The seeds can be planted immediately or saved until the following spring.
How to Grow Burdock From Seed
Plant burdock seeds about 1/2 inch deep and at least 8 inches apart. Keep the soil moist until germination, which takes no more than seven days. Once the seeds sprout, almost no care is required. The roots will be ready for harvest in about 90 days, though young leaves can be picked much earlier.
Common Pests and Diseases
When a plant earns a reputation as a weed, it usually is fairly immune to diseases and pests. Burdock is no exception. Common pests such as slugs, aphids, and mites may affect burdock, but they rarely kill the plant. Somewhat unique to burdock is the fondness that four-lined bugs have for it. These pests can do serious damage to leaves, then overwinter to resume their attack the following spring. Neem oil is the best treatment for four-lined bugs.