Reference my blog post on Parsnip Predator. Wendy Walker If the taproot is “sliced” and not fully removed, won’t the plant grow back? I’m primarily concerned with burdock, which you mentioned, as our new property has a large patch of this.”
I googled for manual control of burdock and came across this page Green Machine Fame — DIY Parsnip Predator. It seems to say that the taproot is sliced.
Also, according to a fact sheet compiled by Aaron Ide, the manual way is to control by hand pulling, chopping, or hoeing as long as the growth point, which is right at the ground level is removed. Mowing can be effective if repeated multiple times. (Invasive Species Fact Sheet – Common Burdock repaired by Aaron Ide).
I found an interesting write-up on How to Control Burdock Weed:
“To pull the plant, grip the base of the leaves. Firmly pull up the plant, applying pressure evenly all around. This should be done as slowly as possible to ensure that the root doesn’t break as you pull.
Once the plant is pulled up but not disturbed, dig around the root with a spade. Dig widely and deeply enough to expose the entire root. Remember that these plants develop large taproots, so you may need to do a lot of digging.
Once the root is exposed, pour undiluted, distilled white vinegar on the base. Carefully pour the vinegar between the leaves of the plant. Aim to cover the heart of the foliage and root system as much as possible.
Allow the dying plant to sit in place for two days. During this period, the leaves will soften and begin to turn brown. As the foliage changes color and dies, pull the leaves and any connected burdock roots.”
Watch out! The thing that happens is its horrific effect on the biologic organisms in the soil. The acetic acid of vinegar will kill burdock by lowering the soil pH. But be careful not to put it on the ground (or other plants). It will lower the pH which is death to the mycorrhizae of the soil. Better to use a spade to slice off the root, as long as the growth point is removed, and just put the vinegar on the root.
Common Burdock (Arctium minus)
Common burdock grows along roadsides, ditch banks, stream banks, old fields, waste places, and neglected areas. It can be found in full or partial shade. Common burdock weed is a biennial plant and is invasive. First-year plants form large rosettes, and new growth is visible anytime. Large arrow-shaped leaves grow close to the ground, and are very hairy on the undersides. The second year, a six- or seven-foot tall, hairy, flowering stalk is formed. It blooms from July to October. The flowers are pink to purple and are enclosed in a prickly burr. The light brown seeds have hooks that can attach to clothing or animal fur.
It reproduces by seeds, and one plant can produce over 15,000 seeds. This is the problem — large, thick taproots branch out in all directions, and digging them is no easy task. As always, dispose of the plant in a garbage can.
Common burdock can cause allergic reactions in some people if the bristles contact the skin. And it acts as a secondary host for pathogens leading to powdery mildew and root rot in other plants.
Note: Dr. Don Morishita, University of Idaho professor of weed science says, “Burdock is a bare-ground plant; it doesn’t grow well where there’s a lot of grass cover or competing plants. Don’t use anything that would kill the grass, because grass tends to inhibit regrowth of burdock.” (Canadian Cattlemen).
Here’s a YouTube film of: “as long as the growth point, which is right at the ground level is removed.”
Transmittal photo by Pethan by courtesy of Wikimedia.