The First Weed of Spring?

By Larry Hodgson

I just know you’re so looking forward to this: the blooming of the first weed of spring!

Yes, the very first flower to bloom in many gardens is coltsfoot (Tussilago farfara). Native to Europe and western Asia, It’s now well established as a noxious weed all over the world.

Many people, in fact, possibly most, mistake it for a dandelion. And indeed, the yellow inflorescences certainly look a lot like dandelion blooms, but there is a huge difference. But where the leaves? Dandelions (Taraxacum officinale) produce their rosette of toothed green leaves first, then the clusters of flowers appear. Coltsfoot looks leafless when it blooms. The large, broad, very undandelionlike leaves appear later.

However, in fact, the small scales that cover the flower stems are tiny leaves. So, as it blooms, coltsfoot isn’t as leafless as it appears.

Coltsfoot (Tussilago farfara) is, in many areas, the very first flower of spring. Its charming yellow flowers emerge very early. Often in February in mild climates, yet as late as May in cold ones.

It’s not just the bright yellow blooms that resemble dandelion flowers. After they finish flowering, they also bear fluffy white seed heads like those of a dandelion. Add to that the fact the two plants belong to the same family, the Asteraceae, and you definitely have the potential for confusion.

This curious habit of blooming well before the foliage appears lead to the Romans calling coltsfoot Filius ante patrem (son before father).

Two Different Plants?

Coltsfoot flowers looking like dandelion flowers are doubly confuses a lot of people. When the leaves do appear, they think that the toothed more-or-less heart-shaped leaves belong to some other plant.

At this stage, it’s easy to confuse coltsfoot with the butterbur (Petasites hybridus), because their leaves are similar. This is another common weed/medicinal plant, although t’s more common in Europe than North America. For a long time, the two plants confused even taxonomists. They originally called butterbur Tussilago hybrida, believing it to be a hybrid of coltsfoot. Today, we know that the name hybrida was a poor choice. That’s because, in spite of the name hybrida, butterbur is not a hybrid, but a species. And that coltsfoot and butterbur are only cousins several times removed.

The leaves are what give the plant the common name coltsfoot. With a bit of imagination, you can (sort of) see the shape as being that of a horse’s hoof… with teeth. To further distinguish coltsfoot from other pretenders, turn a leaf over. You’ll see they’re felty and white on the underside. The upper side too often has a bit of felty white hair. However, that’s most obvious on young leaves.

From Useful to Weedy

Coltsfoot is of Eurasian origin. European settlers introduced it into North and South America as a medicinal plant over a century ago. It has long since escaped culture and become a widespread weed, especially in clay and moist soils.

A pioneer plant, it often appears in disturbed soils, especially around construction sites. With its dense broad leaves, it chokes out native plants. It sometimes comes to cover vast surfaces to the exclusion of any other plant. It’s a sun lover, though. It therefore it tends to gradually disappear as trees and shrubs move in and create dense shade.

Medicinal Use

Coltsfoot has a long history of medicinal use, especially as an antitussive. In fact, the name Tussilago comes from the Latin tussis (cough) and agere (to chase), because it “chases coughs”.

Even today, the plant remains very popular in herbalism. Both fresh and dried leaves, rhizomes and flowers serve as antitussives, demulcents, expectorants and tonics. The flowers and young leaves are edible and you can even use them as vegetables.

However, all the parts contain alkaloids that are toxic to the liver. People with liver problems or pregnant or lactating women should not use coltsfoot. Nor is its long-term use recommended.

How to Control It

Coltsfoot generally arrives in gardens through transported soil contaminated with rhizomes. But it can also spread through the air thanks to the silky hairs that carry the seed far and wide.

Once established, this spring-flowering weed expands via underground rhizomes. Since these can dip down to up to 10 feet (3 m) deep, obviously hoeing is not going to control coltsfoot. In fact, hoeing, cultivating or — worse yet! — using a rototiller often worsen the problem. That’s because those tools tend to chop the rhizomes into pieces, yet any piece left in the soil will produce a new plant. Thus, often the more you cultivate, the faster coltsfoot spreads.

You’ll have more success to cutting back every leaf you see, repeating again and again. Just snip each one off at the base. That prevents the plant from carrying on photosynthesis, its only source of energy. The inability to photosynthesize will gradually exhaust the rhizome.

Or, more simply, cover the ground with a black tarpaulin or piece of old carpet starting in the spring as the leaves of this weed emerge. Now, leave this opaque cover in place for at least one year. (Two years may be necessary if the plant is well-established.) Again, since it won’t be able to carry out photosynthesis, this will exhaust and kill the rhizomes.

Coltsfoot has the reputation of being difficult to kill with herbicides, but some people less environmentally concerned than myself have reported success by treating the young leaves with glyphosate.

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So, is coltsfoot a beautiful harbinger of spring, a useful medicinal plant or a weed to eliminate? It’s all three, of course. How you see it depends on your attitude, your needs and your expectations.

Adapted from an article originally appearing in this blog on April 23, 2017.