Horseweed, also known as Erigeron canadensis and formerly as Conyza canadensis, is a widespread, native, edible wild plant in the greater Aster family, Asteraceae. In some areas it's known as fleabane, butterweed, mare's tail or colt's tail.
It's incredibly abundant as it grows natively in the 48 continental states, and has been introduced into Alaska and Hawaii. In Canada, you can find it all throughout British Columbia and P.E.I. and along the southern edges of every Provence except Labrador, Nunavut and the Northwest Territories. It can be found throughout Mexico and in most of the non-island Central American Countries.
It's almost certainly in your neighborhood.
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| Horseweed patch from my yard, early May |
Horseweed gets little attention in the foraging community, with no really good reason as to why. It's easy to identify, less bitter than the well-known dandelion or plantain, more flavorful than clover, and provides more food than wood sorrel. Despite this, horseweed is only barely mentioned, while those others are brought up every season.
Perhaps it's because horseweed has an unpleasant tendency to grow in some of the least savory of places, including out of sewer grates in the middle of dense and dirty cities. In fact, while I will often find a plant or two on my neighborhood stroll, I often find horseweed growing most densely and abundantly in urban environments: city parking lots, sewers and underneath highway overpasses.
Horseweed is actually quite popular in the survivalist communities, though not as food! But more on that later.
Fortunately, a large patch recently chose to grow right in my own yard! So I've finally been able to see what all the fuss is about, and, let me tell you, this is one tasty little (actually, BIG) weed!
Horseweed taste; edible and medicinal uses
When plants are quite young, 3-4 inches, you can use the whole plant. The central stem gets tough and stringy very quickly, after the plants are around 5 inches high, you will only want to use the leaves. Once the plant is over a foot high or so, you will only want to use the leaves at or near the top, the rest will be dry and flavorless. Once the plant is flowering, it's no longer good for food.
Apparently horseweed is most commonly steeped as a tea, though I only recently tried it that way.
Horseweed can also be used as a flavorful herb, which is how I've been applying it. Simply strip the leaves off the central stalk, chop and add to your dish. I would describe the flavor as being a bit like oregano, but with a freshness like parsley, some almost citrusy brightness and, at the back of the pallet, some anise or tarragon flavor. For me this taste only ever comes at the end of the meal, which is interesting.
Once the flower stems form the leaves are no longer flavorful, but you can harvest the flower buds. These can be added directly into dishes as a vegetable, or pickled if you like. Make sure to get the buds and not the post-bloomed flowers.
Horseweed lends itself to Italian and Indian dishes for sure and I'm looking to branch out further in my experimentation.
Horseweed identification
Growth and Stem features
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| Hairy stalk |
Horseweed grows as a single, straight central stalk, no branching until flowering- Horseweed can grow up to 8 feet tall, but will most often flower between 4 and 5 feet, though you won't want to be harvesting when it gets that old
- When fully grown, the stalk will develop a hollow core, but again, you probably won't want to eat the plant at that stage.
- The stalk is quite hairy, and have shallow vertical grooves or striations running up the whole length
- The leaves grow directly off the stem on slender petioles (leaf stems), no fibrous stems
- The leaves rotate around the stalk as they grow, they do not grow in opposite pairs
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Horseweed leaves | Left: young leaf, still a little rounded
Center: assorted mature leaves to show variations
Right: leaf detail to show barbs |
Leaf features
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Hairy leaf underside and edges,
also note the veins that run parallel to the leaf edge |
- Horseweed leaves are lanceolate, which is to say they are much longer than they are wide; they will become even more so as they age
- Like the stalk, the leaves also have hair, though only on the underside and around the edge of the leaf, not on the top side.
- Horseweed leaves are sometimes described as serrated (like the edge of a saw or a bread knife), but I think this is misleading; rather, they have occasional "barbs" on the leaf edges, anywhere from 2-6 per leaf, (older leaves can have 8)
- These barbs start out as small triangles, but will develop a more fish-hook shape as the leaf ages and grows larger
- One of the best identification features is the randomness of these barbs; almost every leaf will be unique in number of barbs, unique barb positioning, and unique barb size
- All leaves will have prominent veins that run parallel to the central vein, and to the leaf edges; this is easier to see on the underside of the leaves
Flowers
- Before flower buds form, horseweed will start to grow lots of small stems/branches at the top of the stalk. These stems will be 4-12" or so long, and will vary in length with the height of the plant.
- Once these stems form, the plant is no longer good for food as the leaves will become papery and flavorless
- If you are familiar with the aster family as a whole, horseweed has very typical aster flowers - the petals are so narrow they almost appear like hairs or lashes around the bloom
- The petals are white and the centers are yellow
- Each flower is about the size of an American or Canadian dime
- Once bloomed, the flowers will turn into puff heads, similar to dandelion's, but smaller
Look-a-like plants
Note: as long as you are careful about looking for hair, there are no poisonous look-a-likes for horseweed, though there may be allergens that effect some people strongly, even dangerously, on an individual basis.
