| Scientific Name | Common Name(s) | Life History | Growth Form | |
|---|---|---|---|---|
|
Rhamnus alaternus | evergreen buckthorn, Mediterranean buckthorn, Italian buckthorn, blow-fly-bush, buckthorn | Perennial | shrub |
|
Rhaphiolepis indica var. umbellata | Japanese hawthorn, yedda hawthorn | Perennial | shrub |
| Rhinanthus minor | Little yellowrattle, Yellow rattle | Annual | forb | |
| Rhododendron 'Electric Lights Double Pink' | Azalea | Perennial | shrub | |
|
Ricinus communis | castor bean, castor oil plant, Higuera, palma-christi , wonder-tree, castor-bean, castor-bean-plant, castor-oil-plant, kasterolieboom (Afrikaans), higuerilla (Spanish), African Coffee Tree, maple weed | Perennial | shrub |
| Robinia pseudoacacia | False Acacia, Black Locust, Yellow Locust | Perennial | tree | |
|
Roldana petasitis | Velvet groundsel, California-geranium | Perennial | shrub |
|
Romulea rosea | rosy sandcrocus, Guildford-grass, oniongrass | Perennial | forb |
|
Rosa multiflora | Multiflora Rose | Perennial | shrub |
| Rosa oxyodon | rose | Perennial | shrub | |
| Rosa rubiginosa L. | Sweet briar, sweet brier, sweetbriar rose | Perennial | shrub | |
|
Rubus ulmifolius var. anoplothyrsus | Elmleaf blackberry, thornless blackberry, Elm leaf bramble | Perennial | vine |
| Ruellia brittoniana 'Chi Chi' | Mexican Petunia | Perennial | forb | |
| Rumex dentatus | toothed dock, Aegean dock, Indian dock, dentate dock | Annual | forb | |
| Rytidosperma caespitosum | Wallabygrass, Tufted wallaby grass, Ringed wallaby grass, Whitetop | Perennial | grass | |
|
Salpichroa origanifolia | cock's eggs, pampas lily-of-the-valley, cojón de gallo (spanish, Bolivia, Santa Cruz), lily of the valley vine, lily-of-the-valley-vine, pampas lily of the valley | Perennial | vine |
| Salsola ryanii | prickly Russian thistle, tumbleweed | Annual | shrub | |
|
Salsola soda | glasswort, oppositeleaf Russian thistle, agretti, Friar's Beard | ||
|
Salsola vermiculata | shrubby Russian thistle, Mediterranean saltwort, Damascus saltwort | Perennial | shrub |
|
Salvia aethiopis | mediterranean sage, african sage | Perennial | forb |
|
Salvia verbenaca | vervain sage, wild clary | Perennial | forb |
|
Salvia x sylvestris 'Mainacht' MAY NIGHT | May Night sage, meadow sage, violet sage, wood sage, woodland sage, balkan clary | Perennial | forb |
|
Sambucus tigranii | red elder, elderberry, Tigran's elder, Caucasian elder | Perennial | shrub |
| Saponaria ocymoides | rock soapwort, tumbling-Ted | Perennial | forb | |
|
Scabiosa atropurpurea | Pincushion flower, mourningbride, sweet scabious, mournful-widow, pincushions, purple pincushion, Pincushion plant | Perennial | forb |