Cottonwood (Populus deltoides) is dioceous: male and female reproductive organs reside on separate plants.

Males produce pollen; females produce eggs that, if pollinated (fertilized), yield fruits.

Sometimes a "delta"-shaped leaf may host a parasitic leafminer who spends its larva stage within the epidermal layers, feeding on the mesophyll cells.

Juicy buds may be nibbled by Ruffed Grouse, perching precariously on the branches.