Herbs O

Oak Quercus alba	*Oak Quercus prinus	*Oak Quercus spp.	*Oak Quercus velutina	Oak Bark Quercus robur
Oakmoss Evernia prusnatri	Oat Avena fatua	*Oat Avena sativa	Oat Bran Avena sativa	Oatstraw Avena Sativa
Obedient Plant Physostegia virginiana	Ocimum 'African Blue' Ocimum kilimandscharicum x. O. basilicum	Ocimum 'Dark Opal' Ocimum kilimandscharicum x. O. basilicum	Ocotillo Fouquieria splendens	Oil Nut Junglans cinerea
Okra Hibiscus esculenta	Old Maid Catharanthus roseus	Old Man Artemisia abrotanum	Old Man's Pepper Achillea millefolium	Old Warrior Artemisia pontica
Old Woman Artemisia absinthium	Old Woman's Broom Turnera diffusa	Oleae Folium Olea europaea	Olibanum Boswellia sacra	Olive Olea europaea
Olivier Olea europaea	Onion Allium cepa	*Onion Allium cernuum	Ontario Poplar Populus x candicans	Opium Poppy Papaver somniferum
Orach Atriplex hortensis	Orange Citrus sinenis	Orange Milkweed Asclepias tuberosa	Orangeroot Hydrastis canadensis	Orchid Habenaria ciliaris
Ordeal Bean Physostigma venenosum	Oregano Origanum vulgare	Oregon Grape Mahonia aquifolium	Oriental Bunching Onion Alliam fistulosum	Oriental Bush Cherry Prunus japonica
Oriental Sweet Gum Liquidambar orientalis	Origano Origanum vulgare	Origanum 'Norton Gold' Origanum 'Norton Gold'	Orpine Sedum purpureum	Orris Iris germanica
Ortie Urtica dioica	Osceola's Plume Zygadenus densus	Oshá Ligusticum porteri	Ostrich Fern Pteretis pensylvanica	Oswego Tea Monarda didyma
Our Lady's Keys Primula veris	Our Lady's Tears Convallaria majalis	Our Lord's Candle Yucca whipplei	Oval-leaf Buchu Agathosma Crenulata	Owl's Clover Orthocarpus purpurascens
Oxeye Adonis vernalis	Ox-Eye Chamomile Anthemis tinctoria	Ox Eye Daisy Chrysanthemum leucanthemum	Oxlip Primula veris	Oyster Plant Tragopogon porrifolius