The Great Sunflower Project

Your garden could be a refuge for bees — or a hazard. The difference is often a single product on a store shelf.

Three things you can do right now

You don't need a chemistry degree or a farm. These three steps make your garden genuinely safer for the bees you're counting — and for every bee that finds it.

  1. Check your labels before you buy. Neonicotinoids hide under many names: imidacloprid, clothianidin, thiamethoxam, acetamiprid, dinotefuran, flupyradifurone, sulfoxaflor. They appear in grub killers, soil drenches, systemic rose sprays, and "tree and shrub" treatments sold at every hardware store and garden center. If you see any of those words in the active ingredients list, put it back. See our full list of common garden products to avoid.
  2. Ask before you buy a plant. Many flowering plants at nurseries — including plants in full bloom — have been pre-treated with systemic neonicotinoids by the grower. The pesticide is already in the pollen and nectar when the plant hits the shelf. Ask your nursery whether their plants are treated, or look for certified organic stock.
  3. Choose untreated seed. Treated seeds are sometimes coated with a colored dye — but not always. Buy certified organic seed for sunflowers and bee-attracting flowers, or confirm explicitly with the seller that seeds were not treated.

Join the study — and make your counts count double

The Great Sunflower Project is one of the only citizen science programs in North America tracking how pesticide use in ordinary gardens affects pollinator visitation rates in real time. Your backyard data feeds directly into peer-reviewed research.

To participate in the pesticide study specifically:

  1. Plant Lemon Queen sunflowers — our standardized study flower. Using the same variety across all sites is what makes the data comparable. A packet of seed costs a few dollars and yields weeks of counts.
  2. Use neonicotinoid-free seed. Buy certified organic, or verify with your seed supplier. This is the control that makes the science valid.
  3. Submit at least 3 counts of at least 5 minutes each. Multiple counts from the same site are far more powerful than a single observation — they account for day-to-day variation and give us a genuine estimate of pollinator activity at your location.

Large gaps remain in our data, especially in the Midwest and Southeast. If you live in these regions — or know a gardener, teacher, or community group who does — sharing this page might be the most useful thing you do for bee science this season.

Register to participate — it's free →

Why this matters: what we've found — and what science now knows

Neonicotinoids became the world's most widely used class of insecticides for a reason: they work well on pest insects, they're easy to apply, and they were assumed to be relatively safe for non-target species at the low concentrations found in pollen and nectar. That assumption has not held up.

What your data showed us

Using observations submitted by Great Sunflower Project participants across the country, we found two things that the pesticide industry did not expect citizen science to detect:

  1. Neonicotinoid use decreases honey bee visitation rates — and this effect cannot be explained away by differences in land use, climate, or habitat quality.
  2. Local pesticide use creates local pollination deficits. In areas with heavy neonicotinoid use, pollination services are measurably diminished — which has real consequences for the gardens, farms, and wild plants that depend on them.

Your counts produced those findings. Every observation you submit is a data point in a scientific record that otherwise wouldn't exist.

What a decade of research has added

The science has moved fast. Here is what researchers now know about what neonicotinoids do to bees at the concentrations found in treated flowers — concentrations too low to kill a bee outright, but not too low to matter:1–9

  • They get lost. Neonicotinoids block retrieval of navigation memory. Bees exposed to field-realistic doses are significantly less likely to find their way home after foraging.4
  • They forget flowers. Bumblebees chronically exposed to low doses show measurably impaired learning and memory for flower recognition — they become less efficient foragers over time.5
  • They stop dancing. The waggle dance — the honey bee's precise communication about food location — is disrupted. Exposed bees do fewer circuits, recruiting fewer foragers, causing food shortages within the colony.3
  • Their immune systems weaken. Sub-lethal exposure suppresses immune function, leaving colonies more vulnerable to the pathogens and parasites that are already stressing bee populations.1
  • Queens produce fewer queens. In bumble bees, neonicotinoid exposure reduces new queen production — a slow-moving consequence with outsized effects on wild population recovery over years.2
  • Larvae die at higher rates. Chronic exposure to thiamethoxam severely impairs larval survival and adult emergence, gradually shrinking colonies from the inside.6
  • Their clocks break. Neonicotinoids disrupt bee circadian rhythms and sleep, impairing the internal timing systems that govern foraging, navigation, and memory.7
  • Fungicides make it worse. Common fungicides applied alongside neonicotinoids multiply their toxicity — an interaction that standard regulatory risk assessments have historically failed to account for.8

And one more thing: the official risk assessments were wrong. A 2023 analysis found that regulatory safety thresholds are calibrated almost entirely on honey bees — which are not representative of the hundreds of wild bee species actually at risk. Native solitary bees and bumble bees are, in many cases, substantially more sensitive.9

References

  1. Ahsan, Z. et al. (2025). The sublethal effects of neonicotinoids on honeybees. Biology, 14(8), 1076. doi:10.3390/biology14081076
  2. Woodcock, B. A. et al. (2016). Impacts of neonicotinoid use on long-term population changes in wild bees in England. Nature Communications, 7, 12459. doi:10.1038/ncomms12459
  3. Crall, J. D. & Raine, N. E. (2023). Neonicotinoid treatment impacts coordination among worker bees. Proceedings of the Royal Society B.
  4. Binder, M. et al. (2014). Neonicotinoids interfere with specific components of navigation in honeybees. PLOS ONE. PMC3960126
  5. Stanley, D. A. et al. (2015). Bumblebee learning and memory is impaired by chronic exposure to a neonicotinoid pesticide. Scientific Reports. PMC4644970
  6. Beyond Pesticides (2025). Neonicotinoid insecticide linked to honey bee decline, threatening reproductive function of hive. beyondpesticides.org
  7. Tackenberg, M. C. et al. (2020). Neonicotinoids disrupt circadian rhythms and sleep in honey bees. Scientific Reports. PMC7578099
  8. Tosi, S. et al. (2024). Effects of common co-occurring pesticides (a neonicotinoid and fungicide) on honey bee colony health. PLOS ONE. PMC11066323
  9. Wood, T. J. et al. (2023). Risk assessments underestimate threat of pesticides to wild bees. bioRxiv. doi:10.1101/2023.09.15.557615
  10. Goulson, D. (2013). An overview of the environmental risks posed by neonicotinoid insecticides. Journal of Applied Ecology, 50, 977–987.
  11. Potts, S. G. et al. (2010). Global pollinator declines: trends, impacts and drivers. Trends in Ecology & Evolution, 25, 345–353.