Following the summer I start to look dead,
But it’s just the beginning of my time to spread!
My burs will be carried through rain and snow,
After all, it was me who inspired Velcro!
Common Burdock is one of the most infamous invasive species in Whistler and for good reason. This species produces annoying burs that stick to clothing, hair, and fur – in fact, they were the inspiration behind the invention of Velcro! The pesky burs allow them to spread over great distances quickly. They’re such a problem that we have developed a program specifically designed to remove Common Burdock from Whistler called Banish Burdock (formerly Adopt-a-Trail) that runs during the summer.
Common Burdock is also widely known as a medicinal plant and for its edible taproot. It’s thought that this species was originally accidentally transported from Europe to North America; the earliest reported sighting is from 1638! Despite its many uses, Common Burdock outcompetes other plant species, reduces available forage for wildlife and livestock, and can ensnare birds and bats in its burs if left unchecked.
Common Burdock is generally thought of as a biennial plant that doesn’t grow flowers until its second year (more on that in a second). In its first year, the plant grows into a rosette of large leaves that resembles rhubarb and develops a thick, fleshy taproot. In its second year, the plants grow to be 0.5 – 3m tall, and develop clusters of green burs that each bear a purple flower. After the flowers mature, the burs dry out and turn brown and brittle, clinging to everything with long, hooked bristles.
While Common Burdock is typically a biennial plant, in recent years, we have observed that the plant was behaving more like a short-lived perennial. In many instances, Burdock plants would flower in their second year of growth, but they would keep producing flowers the following season instead of dying back as biennials would.
Common Burdock reproduces by seeds, which are carried within their clinging burs. These burs can remain on wildlife (or your socks!) for days and can be carried kilometres away from the parent plant. Burdock plants can also regenerate when improperly removed: if the entire taproot isn’t pulled from the ground, the plant will re-sprout from the remaining taproot fragment and still produce seeds.
This invasive species harms the environment in many ways: when the leaves of Common Burdock decompose, they release a chemical that prevents other plants nearby from germinating and growing (a characteristic called allelopathy). Burdock’s large leaves also cast a lot of shade around them, blocking the sun from other plants and out-competing them. The plant is also a host for powdery mildew and root rot, so if we let it grow near gardens or crops, more valuable plants could be contaminated.
Common Burdock is sometimes confused with the equally invasive Great Burdock, as well as non-invasive Rhubarb and native Cockleburr.
- Great Burdock, which is very closely related to Common Burdock, looks very similar but with larger flowers and burs, and thicker stalks.
- Rhubarb looks similar to Common Burdock, though it is not invasive. It has similar large leaves but without a woolly fuzz on the underside or hollow stems, and doesn’t produce burs.
- Cockleburr, while also having burs, has smaller, spinier leaves than Common Burdock does. It is native to BC.
Per SSISC’s Invasive Plants Priority List, Common Burdock is listed as a species to strategically control throughout the Sea to Sky region. We rely heavily on reports from the public to understand the current distribution of plants in the Sea to Sky and prevent their spread. With that in mind, we invite you to keep your eyes peeled for Common Burdock and report any sightings.
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