Horseweed - Erigeron canadensis (Taxonomy, Characteristics, Invasive, Images, Control)

Horseweed

Also known as: Canadian fleabane, Marestail

Horseweed is a North American herbaceous annual plant with a hairy stem, numerous pointed leaves, and waxy inflorescence. It has been naturalized in Eurasia and Australia, where it is a common weed in urban and agricultural regions. Horseweed can be used in a survival situation to start a friction fire.

Scientific classification

Species

Horseweed (Erigeron canadensis)

Asters bellflowers fanflowers and allies

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Weeds

Weed or not

Annual, Biennial

Lifespan

Herb

Plant Type

Summer, Fall

Bloom Time

Fall

Harvest Time

50 cm to 1.5 m

Plant Height

50 cm

Spread

Green

Leaf Color

1 cm

Flower Size

Gold, Yellow, Silver, Gray

Fruit Color

White, Yellow

Flower Color

Green, Red, Brown

Stem Color

Winter dormancy

Dormancy

Deciduous

Leaf type

20 - 35 ℃

Ideal Temperature

Images of Horseweed

Attributes of Horseweed

Growth Rate

Demonstrating a rapid growth rate, horseweed flourishes remarkably from spring to fall, producing a high volume of leaves, and quickly bolting to great heights. It's common to observe sudden bursts of growth during these seasons, often coupled with the development of small white flowers. The robust growth seen in summer often continues into fall, indicating horseweed's adaptability to varied seasonal conditions.

Distribution of Horseweed

Distribution Map

Horseweed is naturally distributed through much of the New World, where it grows in open areas. This plant has spread around the rest of the globe, where it can become weedy or invasive in agricultural contexts, grasslands, and disturbed areas. Many European countries have listed horseweed as invasive.

Native

Cultivated

Invasive

Introduced

No species reported

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Habitat

Waste and cultivated land, walls

Hemisphere Trend Curve

Northern

Sorthern

Culture

Economic Value

Stems and leaves of horseweed can be used as fodder.

Garden Use

Horseweed is a tolerant, low-maintenance plant. Often used in the garden to attract wildlife and pollinators, this plant can be put in a sunny or partially shaded area with well-draining soils. Horseweed is drought-tolerant and can be planted in areas where erosion control is needed.

Symbolism

Sanctity, purification, driving away the unwanted

Interesting Facts

In the autumn fields and tea orchards, there are blooming crowds of inconspicuous little wildflowers dotting the weeds called horseweed.

Name Story

Mare's tail||Horseweed: If you observe the plant closely, you discover that its stalk has many branches and the branches all grow upwards. What makes it magical is that each branch is covered with short hairs. When the sun shines on it, the shadow cast on the ground looks like a horse tail. So, it is called mare's tail or horseweed.

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Toxicity

Horseweed has low-severity toxicity to humans when leaves are ingested, leading to mild symptoms like a runny nose or sore throat. Horseweed is toxic to cats and dogs, primarily affecting them upon ingestion of leaves, showing various signs of physical distress. Immediate veterinary care is crucial if pets consume horseweed. Preventing access to horseweed helps ensure their safety.

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Weed Control

Horseweed is a common landscape and agricultural weed, mainly found on undisturbed lands. It is infamous for being the first weed to develop resistance to the widely used herbicide, glyphosate. What's more, the germination time is flexible, so horseweed can emerge in all seasons except winter, and the seeds spread efficiently like dandelion seeds.

Horseweed has been spreading outside of its native range for centuries and can now be found in grasslands, fields, and many disturbed areas in Europe, Asia, Australia, northern Africa, and tropical parts of the Americas. It is considered an agricultural weed both in its native and naturalized range.

How to Control It

The optimal season for dealing with horseweed is late spring or early summer, before it reaches the budding stage. This is important as the plant spreads its seeds through its flowers. Following are some methods to remove or control this plant:

Handpulling: Put on a pair of gardening gloves and gently pull the horseweed from the soil. Ensure you remove the entire root system to prevent it from regrowing.
Hoeing: Use a garden hoe to cut the plant at its roots. Aim to do this before the horseweed produces flowers to prevent seed dispersal.
Smothering: Cover the area around the horseweed with a thick layer of organic mulch like compost or straw. This blocks sunlight, stifering the plant's photosynthesis.
Solarizing: Water the area around the horseweed thoroughly and cover it with a clear plastic sheet. The intensified heat from the sun will cook and kill the plant.
Using Cover Crops: Plant a cover crop that quickly outcompetes the horseweed for nutrients and sunlight.

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Quickly Identify Horseweed

Rosette of hairy leaves in winter transitioning to slender upright form in spring.

Small white flowers with yellow disk centers in inconspicuous clusters along stems.

One-seeded achenes with yellow-gray color and fluffy white hairs for wind dispersal.

Linear green leaves with smooth or toothed margins, averaging 2-3.5 inches in length.

Light green angular stem with fine white hairs, unbranched except near flower formations.

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Care Guide for Horseweed

Twice per week

Water

Full sun

Sunlight

20 - 35 ℃

Ideal Temperature

Water: Horseweed thrives in conditions replicating its native habitat with periodic rainfall and well-draining soil. It prefers drier conditions, benefiting from moderate watering twice a week. Typically grown outdoors, horseweed adapts well to varying rainfall, enhancing local ecosystem diversity.

Propagation: Horseweed propagates easily through sowing in spring, with seedlings appearing in 2-3 weeks. This species requires no special propagation techniques, making it straightforward for growers.

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Images of Horseweed

Attributes of Horseweed

Distribution of Horseweed

Culture

Toxicity

Weed Control

Quickly Identify Horseweed

Care Guide for Horseweed

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