Metallic Green Sweat Bees: Fall Garden Pollinators

Identification

Metallic green sweat bees (Agapostemon spp.) are medium‑sized (¼–½ inch), brilliant emerald green head/thorax. Females: black or green abdomen with white bands. Males: black abdomen with yellow/cream bands, yellow legs, no pollen hairs.

Life Cycle

Mated females overwinter underground, emerge mid‑late May (earlier south). Nest in bare, uncompacted soil—often in aggregations. Some species communal. One or two generations per year. Males die in fall; mated females overwinter.

Foraging and Pollination

Effective pollinators on open, accessible flowers (especially Asteraceae). Medium size and long tongue reach complex flowers. Need continuous bloom spring–fall.

Attracting Them

• Nesting habitat: Leave bare, sandy/loamy soil patches undisturbed.
• Pesticide‑free: No insecticides, especially on flowers.
• Forage plants:
  • Late spring: Spiderwort, Canada anemone, pale purple coneflower, beardtongue, dogwood.
  • Summer: Gray‑headed coneflower, black‑eyed Susan, coneflower, purple prairie clover, wild quinine, ironweed, vervain, smooth oxeye, cup plant.
  • Late summer/fall: Goldenrod, common boneset, asters (any species).

Spotting Them

Look for bright green bees on composite flowers. Larvae are grub‑like, pale, unseen underground. Nest entrances in bare soil.

Regional Notes

~14 species north of Mexico; 44 worldwide. Western hemisphere from central North America to South America. Habitats: woodland edges, gardens, meadows, prairies, old fields.