

Fivehorn Smotherweed Bassia hyssopifolia
Fivehorn Smotherweed is an introduced annual herb, found in Canada, Hawaii, and the lower 48 states. It grows to 0.8 ft and blooms Jun in part shade – shade, with black fruit.
More about this plant
Bassia hyssopifolia is a species of flowering plant in the family Amaranthaceae, known by the common names five-horn smotherweed, five-hook bassia, and thorn orache. It is native to parts of Asia and Eastern Europe, and it is known on other continents as an introduced species, including North and South America and Australia. It is a weed, invasive at times. Wikipedia →
Fivehorn Smotherweed is flagged invasive in the U.S. These natives fill a similar niche — same growth habit, bloom season, height, and region — so you keep the look and feed local wildlife instead of spreading a problem.
Growing & care
USDA PLANTS · TRY- Sun
- Part shade – shade
- Soil & moisture
- Medium moisture
- Soil pH
- 6.5–9.1
- Fertility need
- Low
- Adapts to
- Medium (loam), Fine (clay)
- Hardiness
- USDA zone 13+
- Height
- 0.8 ft
- Spread
- None — clumping
- Growth rate
- Rapid
- Growth form
- Single stem
- Lifespan
- Annual
- Foliage
- Broadleaf · coarse texture
- Active growth
- Summer
- Fruit
- Black persists into winter
- Flower colour
- Green AI AI image-analysis of community-science photos — lower-confidence (a more subjective call, often an inconspicuous flower); not a botanical record
- Propagate by
- Seed
- Seed starting
- No stratification needed
- Seeds ripen
- Summer seed-collection / harvest window
- In the trade
- No known commercial source
- Resprouts if cut
- No
Sow timing keys off your local last- and first-frost dates.
Wildlife & pollinators
How pollinator value is scored →Wildlife & visitors 1 bird
Open records of who else uses Fivehorn Smotherweed — a generalist food-web signal, kept separate from the keystone Ecological Value.
Recorded eaten by 1 bird species (fruit, seed, browse):
How we know this (3) Methods & honest limits
A recorded categorical fact: each species is tagged C3 (standard), C4 (heat/water-efficient) or CAM (succulent, night-time CO₂ uptake) — or a facultative combination. We only show a trait card for the noteworthy C4/CAM cases; C3 is the unremarkable majority, kept in the data but not surfaced as a card.
We take the plant’s U.S. county range and look up each county’s long-term climate, then summarise: native rainfall = the median annual rainfall across its counties; heat tolerance = the warm end (90th percentile) of average temperature across its range (mirroring how our cold-hardiness floor uses an extreme). Counties + medians blunt the roadside/observer bias that makes point-level climate unreliable. Needs at least five placeable counties.
Honest limits: A realized, sampling-biased niche (where it has been recorded, not its physiological optimum), and county climate is coarse — large Western counties span deserts and mountains. Derived guide, never a measured fact.
McKenzie et al. assigned each species a flower colour with a GPT-4V vision model over iNaturalist photos. We use the confident tier plus a separately-labelled lower-confidence top-up (mostly inconspicuous green/brown flowers), and render it as a small tint — never as an asserted fact, and kept out of the written synopsis.
Honest limits: AI image inference (~87% expert agreement on the confident tier); a decorative, confidence-tiered indicator, not a measured trait.
Sources for this entry (30) Open & cited
Cite this page Open data, please attribute
PlantKey’s data is open under CC BY-SA 4.0 — free to reuse and adapt, with attribution and the same licence. Photos keep their own per-image licence + credit (see Sources above).
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