O-zumi          

Oakleaf Mountain Ash          

Oakwoods Dewberry          

Oblongfruit Serviceberry          

Ocala Blackberry          

Oceanspray      

Oemleria          

Okanagan Valley Hawthorn          

Okennons Hawthorn          

Oklahoma Blackberry          

Oklahoma Plum          

Old Mans Whiskers      

Oldfield Blackberry      

Oldfield Dewberry          

Oldmaid Hawthorn          

Olympic Mountain Rockmat          

Oneflower Cinquefoil          

Oneflower Kelseya          

Oneseed Hawthorn      

Ontario Hawthorn