Oleander (spp.) Oleander 'Apple Blossom'
Oleander 'Calypso' Oleander 'Isle of Capri'
Oleander 'Petite Pink' Oleander 'Petite Salmon'
Oleander 'Sister Agnes' Oleander, Mexican
Oleander, Yellow Oleaster (spp.)
Oleaster 'Frederici' Oleaster Golden
Oleaster 'Yellow Edge Variegated' Oleaster: ebbingeihybrid 'Coastal Gold'
'Oleoides x Shiressii' Spider Flower Olifants River Euphorbia
Olive Holly (spp.) Olive Holly 'Goshiki'
Olive Holly 'Gulftide' Olive Holly 'Kembu'
Olive Holly Variegated Olive Leaf Grevillea
Olive, Fortune's Sweet Olive, Fragrant (spp.)
Olive, Fragrant 'Fudingzhu' Olive, Holly Tea (spp.)
Olive, Holly Tea 'Goshiki' Olive, Holly Tea 'Gulftide'
Olive, Holly Tea 'Kembu' Olive, Holly Tea Variegated
Olive, Sweet (spp.) Olive, Sweet 'Fudingzhu'
Olive, Tea (spp.) Olive, Tea 'Fudingzhu'
Olive, Wild Olive: americanus, Wild
Olive: burkwoodiihybrid, Sweet 'Olivia' Indian Hawthorn
'Olympiad' Old Fashioned Weigela 'Olympic Fire' Mountain Laurel
'Olympic Wedding' Mountain Laurel Omeo Grevillea
'Oneida' Linden Viburnum 'Onondaga' Sargent Viburnum
'Opera' Butterflybush: hybrid 'Orange Aide' Cinquefoil
Orange Ball Tree Orange Bells
Orange Berry Pittosporum Variegated Orange Browallia
Orange Calamondin 'Tiger' Orange Cestrum
'Orange Dream' Japanese Maple 'Orange Fiesta' Bougainvillea: Bougainvillea
Orange Flame Vine Orange Jasmine
Orange Jessamine Orange Panama 'Tiger'
Orange Tower Flower 'Borneo Sunset' Orange, Bitter (spp.)
Orange, Bitter 'Flying Dragon' Orange, Hardy (spp.)
Orange, Hardy 'Flying Dragon' Orange, Japanese Hardy (spp.)
Orange, Japanese Hardy 'Flying Dragon' Orange, Mock (spp.)
Orange, Mock 'Creme De Menthe' Orange, Mock 'Turners Dwarf'
Orange, Mock Variegated Orange, Trifoliat (spp.)
Orange, Trifoliat 'Flying Dragon' 'Orangeade' Rose
'Orchid Beauty' Butterflybush Orchid Rock Rose
Orchid Tree: grandidieri Orchid Tree: ramosissima
Orchid, Philippine Oregon Cedar 'Aurea Densa'
Oregon Grape 'Skylark' Oregon Grape (spp.)
Oregon Grape 'Compactum' Oregon Holly Grape (spp.)
Oregon Holly Grape 'Compactum' Oregon Holly (spp.)
Oregon Holly 'Compactum' 'Oregon Jade' Mugo Pine
Organ Pipe Cactus Oriental Bittersweet
Oriental Paper Bush (spp.) Oriental Paper Bush 'John Bryant'
Oriental Paper Bush 'Winter Gold' Oriental Spice Bush
Oriental Spruce 'Nigra Compacta' Ornamental Peach 'Icicle'
'Oshio beni' Japanese Maple Osmanthus, Roundleaf Holly
Osmoxylon