| Common name (English) | |
|---|---|
| Oenothera glazioviana | Large-flowered Evening-primrose |
| Ononis natrix subsp. natrix | Shrubby rest-harrow, Large Yellow Restharrow |
| Ophrys reinholdii subsp. straussii | |
| Opuntia humifusa | Eastern prickly-pear |
| Origanum onites | Cretan oregano; Greek oregano; pot marjoram |
| Oxalis latifolia | Garden Pink-Sorrel |
| Oxalis pes-caprae | Bermuda buttercup |
| Pandorea jasminoides | Bowerplant |
| Panicum capillare | Witch grass, Witch-Grass |
| Parkinsonia aculeata | Jerusalem thorn |
| Parthenocissus quinquefolia | American Ivy |
| Paspalum dilatatum | Bastard Millet Grass |
| Paulownia tomentosa | Empress tree |
| Perilla frutescens | Beefsteak |
| Phalaris canariensis | Canary grass, Canary-Grass |
| Phillyrea angustifolia | Narrow-leaved mock privet |
| Phoenix canariensis | Canary Island Date Palm |
| Phoenix dactylifera | Date palm |
| Phytolacca americana | Pokeweed, American pokeweed |
| Phytolacca dioica | Ombu tree, Belhambra Tree |