Round-headed Leek (Allium sphaerocephalon)
Key Details
| Taxonomic Groups: | Vascular plant > flowering plant > Herbaceous plant |
| Red List Status: | Vulnerable (Not Relevant) [VU(nr)] |
| D5 Status: | Included in the baseline Red List Index for England (Wilkins, Wilson & Brown, 2022) |
| Section 41 Status: | (not listed) |
| Taxa Included Synonym: | (none) |
| UKSI Recommended Name: | Allium sphaerocephalon |
| UKSI Recommended Authority: | L. |
| UKSI Recommended Qualifier: | (none specified) |
| Red List Citation: | in Stroh et al., 2014 |
| Notes on taxonomy/listing: | (none) |
Criteria
| Question 1: | Does species need conservation or recovery in England? |
| Response: | Yes |
| Justification: | Assessed as VU in England (Stroh et al., 2014) due to its restriction to 1 site (Avon Gorge), where it is restricted to two highly restricted sub-populations. |
| Question 2: | Does recovery/ conservation depend on species-specific actions? |
| Response: | Yes |
| Justification: | Growth of scrub, spread of non-native invasives & impacts of conservation grazing by goats all pose issues for this species |
| Question 3: | At a landscape scale, would the species benefit from untargeted habitat management to increase habitat mosaics, structural diversity, or particular successional stages? |
| Response: | No |
| Justification: | This species would not benefit from untargeted management |
Species Assessment
| Current step on the Species Recovery Curve (SRC): | 6. Recovery solutions trialled |
| Recovery potential/expectation: | Medium-high |
| National Monitoring Resource: | Opportunistic - sufficient |
| Species Comments: | Long considered a native in the Avon Gorge, where two populations survive & inflorescence numbers fluctuate greatly from year to year. Currently considered native or alien. |
Key Actions
Key Action 1
Proposed Action: Survey both sub-populations to assess current conservation status, & risks from invasives (notably scrub, & introduced Allium spp. & Cotoneaster spp.) & impact of conservation grazing (e.g. by goats)
Action targets: 3. National Monitoring Plan agreed and implemented
Action type: Status survey/review
Duration: 1 year
Scale of Implementation: 1 site
High priority sites: Avon Gorge SSSI
Comments: The species fluctuates so widely and is currently negatively impacted by coarse vegetation (native & non-native) and conservation grazing, meriting frequent monitoring
Key Action 2
Proposed Action: Ensure suitable conditions for species at two sub-populations through targeted management (e.g. scrub / tree removal, control of invasives)
Action targets: 6. Recovery solutions trialled
Action type: Habitat management
Duration: 3-5 years
Scale of Implementation: 1 site
High priority sites: Avon Gorge SSSI
Comments:
Key Action 3
Proposed Action: Ensure both wild sub-populations from Avon Gorge are maintained under ex-situ conditions, ideally in Millenium Seed Bank.
Action targets: 5. Remedial action identified
Action type: Ex situ conservation
Duration: 2 years
Scale of Implementation: 1 site
High priority sites: Avon Gorge SSSI
Comments: The species has always been confined to two separate spots in Avon Gorge, so introductions to other sites in gorge should be avoided.
Acknowledgment:
Data used on this website are adapted from Threatened species recovery actions 2025 baseline (JP065): Technical report and spreadsheet user guide (Natural England, 2025). Available here.