Ocean spray 
Oleaster-leafed pear 
Olive leaf fig 
Oneflower Kelseya 
Opposite Leaf Fig 
Oregon cherry 
Oriental Hawthorn 
Osoberry 
Paper mulberry 
Parsley Hawthorn 
Peach 
Pear-leaf Crabapple 
Pennsylvania Blackberry 
Petiolate Fig 
Phoenician Rose 
Physocarpus capitatus 
Poikilospermum suaveolens 
Polylepis rugulosa 
Potentilla diversifolia 
Potentilla geranioides 
Potentilla pusilla 
Prairie Smoke 
Prickly Wild Rose 
Prostrate ceanothus