Felty germander 
Fernandoa madagascariensis 
Field Cow-wheat 
Field woundwort 
Firecracker Penstemon 
Firecracker Plant 
Firecracker-Flower 
Firespike 
Five-leaved chaste tree 
Five-rib Thyme 
Flame Acanthus 
Flame Violet 
Flame Violet 
Flaming Glorybower 
Flatleaf bladderwort 
Flaxleaf monardella 
Flower-of-gold 
Forest germander 
Forsythia × intermedia 
Foxglove beard-tongue 
Fraxinus excelsior 
Fraxinus pennsylvanica 
French Lavender 
Frilly Lepidagathis