Guide to growing garden plants and flowers O
Index of plants garden plants and flowers O
Plants are organised by their common names in the flowers O table. The scientific name is also given.
| Obediant plant - Physostegia | ||
| Ocimum - Basil | Oconee bells - Shortia | |
| October daphne - Sedum | Oenothera - evening primrose | |
| Oil flax - Linum | Onosma - Golden Drop | |
| Orach - Atriplex | ||
| Orange African daisy - Ursinia | Orange clock vine - Thunbergia | |
| Orange Milkweed - Asclepias | Orange Sunflower - Heliopsis | |
| Orchid - Bletilla | Orchis - Green veined orchid | |
| Oregano - Origanum | ||
| Oriental Iris - kaempferi | Oriental poppy - Papaver | |
| Ornithogalum | Orpine - Sedum | |
| Oswego tea - Monarda | Our lady's milk thistle - Silybum | |
| Oxalis - Shamrock and Sorrel | ||
| Ox-eye - Buphtalmum | Ox-eye daisy - Buphtalmum | |
| Oxypatalum - Star of the Argentine | Oysterleaf - Mertensia | |