Norway Maple
Nova Agave
October Daphne
Octopus Agave
Old Gold Pfitzer
Old Man of the Andes
Oldham Bamboo
Oleander
Olive
Orange Crush Day Lily
Orange Flame Kniphofia
Orange Ice Plant
Orange Sedum
Orange Watsonia
Orchid Spot Rockrose
Oregon Ash
Oregon Grape
Oriental Arborvitae
Oriental Fountain Grass