Also known as Argentine Fleabane · Asthma Weed · Buenos Aires Conyza
Flax-leaved Horseweed (Erigeron bonariensis) is a fast-growing annual weed with small daisy-like flowers. It's often found in disturbed areas and can spread rapidly.
At-a-glance light, water, soil, and growing conditions from plant data
Full Sun
100% intensity
Prefers at least 6-8 hours of direct sunlight per day.
Moderate
50% intensity
Water when topsoil is dry, allow to dry slightly between waterings.
Adaptable
50% intensity
Moderate
50% intensity
Prefers average room temperatures between 18-24°C. Can tolerate cooler conditions.
Low
25% intensity
Does not require heavy feeding; fertilize sparingly.
Safety information from plant toxicity data
| Attribute | Value |
|---|---|
| Toxic for humans | No 0/5 intensity |
| Toxic for pets | No 0/5 intensity |
| Edible | No |
Non-toxic
Key traits and growing stats from plant data
Watering, pruning, propagation, and repotting details from plant data
Water consistently when the top 2-3 cm of soil feels dry. Flax-leaved Horseweed tolerates brief dry spells once established, but thrives with regular moisture, especially during warmer periods.
Avoid waterlogging, which can lead to root rot. Reduce watering in cooler months.
Prune to maintain shape and encourage bushier growth, especially if it becomes leggy. Deadhead spent flowers to prevent self-seeding, as it can be an aggressive spreader.
Light pruning can be done anytime during the growing season.
Easily propagated from seed. Sow seeds directly outdoors in early spring or late autumn. Can also be propagated from cuttings taken in late spring or early summer. It readily self-seeds, often becoming naturalized.
Repot seedlings or young plants if they become root-bound, typically every 1-2 years. Use a well-draining potting mix.
Mature plants generally do not require frequent repotting and can be invasive if given too much space.
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Monthly activity intensity for bloom and fruit across both hemispheres.
Flowering & fruiting calendar
Flowering & fruiting calendar
Photos of Flax-Leaved Horseweed (Erigeron bonariensis)
Common names and botanical synonyms
Botanical classification
| Rank | Name |
|---|---|
| Kingdom | Plantae |
| Division | Tracheophyta |
| Class | Magnoliopsida |
| Order | Asterales |
| Family | Asteraceae |
| Genus | Erigeron |
| Species | Erigeron bonariensis |
Similar in genus Erigeron
Answers based on plant encyclopedia data
