Northern or Western Catalpa
Northern Sea Oats, Bamboo Grass
Norway Maple
Oakleaf Hydrangea
October Daphne
Oklahoma Red Bud
Oldham or Giant Timber Clumping Bam
Oleander
Olive, Edible Olive
Orange Crush Daylily
Orange or Brown Sedge
Orchid Spot or Orchid Rockrose
Oregano
Oregano, Wild Marjoram
Oregon Ash
Oregon Grape
Oriental Arborvitae
Oriental Fountain Grass
Oriental Poppy
Oriental Weigela