

Rough Bedstraw Galium asprellum
Rough Bedstraw is a perennial wildflower native to Canada and the lower 48 states. It grows to 5.9 ft and blooms Jul – Sep in full sun, with black fruit. A host for pollen-specialist native bees.
More about this plant
Galium asprellum, the rough bedstraw, is a plant species in the family Rubiaceae. It is native to eastern Canada and northeastern United States, from North Carolina and Tennessee north to Minnesota, Ontario and Newfoundland. It is considered a noxious weed in New York, Pennsylvania and Vermont, and is abundantly common in the other New England states and in sections of the Great Lakes region. It is a perennial herb. Leaves are simple with three or more leaves per node. Flowers have four petals and are white in color. Wikipedia →
Growing & care
USDA PLANTS · TRY- Sun
- Full sun
- Soil & moisture
- Medium moisture
- Soil pH
- 5–7
- Fertility need
- Medium
- Adapts to
- Coarse (sandy), Medium (loam), Fine (clay)
- Hardiness
- USDA zone 4+
- Height
- 5.9 ft
- Spread
- None — clumping
- Growth rate
- Rapid
- Growth form
- Single crown
- Lifespan
- Perennial · moderate
- Foliage
- Broadleaf · fine texture
- Active growth
- Summer
- Fruit
- Black
- Flower colour
- White AI AI image-analysis of community-science photos (~87% expert agreement) — not a botanical record
- Propagate by
- Seed
- Seed starting
- No stratification needed
- Seeds ripen
- Summer – Autumn 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 →❧ Caterpillar hosts ~19 caterpillar species
Galium supports ~19 caterpillar species.
Native butterfly & moth caterpillars are the base of the terrestrial food web — most songbirds rear their young almost entirely on them. As a host for native Lepidoptera this is a moderate genus.
Recorded feeding on Galium in North America, including:
+ 8 more species → ↑ show fewer
✦ Bees specialist-bee host
Specialist native bees depend on it.
Some native bees are pollen specialists (oligolectic) — they raise young only on pollen from particular plant genera. Galium is a recorded specialist-bee host, so losing it can mean losing the bee that relies on it.
How we know this (2) Methods & honest limits
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 (31) 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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