Box Elder (Acer negundo)
Difficulty: ⭐⭐☆☆☆
Seed Collection Time:
Late fall through early winter — typically October to December, though seeds may remain on the tree into mid-winter.
Signs Seeds Are Ready:
Samaras (“helicopter seeds”) turn from light green to tan or brown.
Seed clusters become dry and papery.
Seeds detach easily when gently pulled.
The nutlet inside each samara is firm and fully formed.
Seed Collection Steps:
Collect dry, brown samara clusters directly from branches.
Remove the wings if desired—either form stores well.
Spread seeds on a tray to air-dry for several days.
Store in a labeled paper envelope or breathable container.
Germination Tips:
Box Elder seeds have simple physiological dormancy and need cold exposure.
Best results: fall sowing outdoors for natural overwintering.
Seeds typically germinate the first spring after stratification.
C (60-90): Cold Stratification
Refrigerate seeds 60–90 days at 35–40°F in moist peat, sand, or vermiculite.
After stratification, sow seeds ½ inch deep in moist soil.
Maintain even moisture until germination, which usually occurs in 2–4 weeks.