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| Plant | Origin | Zone | Height | Type | D/M/W |
| Ochroma pyramidale - Balsa | Tropical America | 11 | 30M | ||
| Ocotea coriacea - Lancewood | South Florida, Tropical America | 10-11 | 10M | ||
| Oenocarpus bacaba | N Amazonia | 10B-11 | 20M | Shade | |
| Oenocarpus bataua (mapira clustering) | South American | 10B-11 | 25M | Shade | |
| Olea europaea - European Olive Tree | 9 | ||||
| Onchrosia elliptica - Kopsia | Araiba, Tropical Africa | 9-11 | 7M | ||
| Oncoba spinosa - Fried Eggtree | Tropical Africa | 10B-11 | 6M | ||
| Orania sp | New Guinea | 10B-11B | |||
| Orbigyna guacuyule | |||||
| Oroxylum indicum - Midnight Horror |
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