Ex situ collections:
| Botanical name | Common name | Variety name / Accession name | Accession number | Part of the MLS |
|---|---|---|---|---|
| Rhododendron adenogynum DIELS | Rhododendron | - | 100002 | - |
| Rhododendron adenogynum DIELS | Rhododendron | - | 100003 | - |
| Rhododendron adenopodum FRANCH. | Rhododendron | - | 100004 | - |
| Rhododendron albrechtii (LINDL.) MAXIM. | Rhododendron | - | 100005 | - |
| Rhododendron ambiguum HEMSL. | Rhododendron | - | 100007 | - |
| Rhododendron amesiae REHD.& WILS. | Rhododendron | - | 100009 | - |
| Rhododendron argyrophyllum ssp. nankingense (COWAN) D.F. CHAMB. | Rhododendron | - | 100011 | - |
| Rhododendron atlanticum (ASHE) REHDER | Rhododendron | - | 100012 | - |
| Rhododendron atlanticum (ASHE) REHDER | Rhododendron | - | 100013 | - |
| Rhododendron augustinii HEMSL. | Rhododendron | - | 100014 | - |