Three-cornered garlic: the pretty Schedule 9 plant in half the gardens in South Wales
Allium triquetrum is on Schedule 9 — and most of the people growing it in their gardens have no idea.
Three-cornered garlic is the prettiest plant on Schedule 9 — and the one our customers are most surprised to find they have been growing on purpose. South Wales, Cornwall and parts of the West Country are particularly affected.
Identification
30–50 cm tall, triangular cross-section stem (run a finger up it — you can feel the three faces), drooping white bell flowers with a green centre stripe, distinctive garlic smell when crushed. Flowering March to June.
Why it matters
It out-competes native bluebells, wood anemones and ramsons across woodland and hedgerow edges. The bulbs are persistent and the plant spreads both by seed and by bulb division — a small patch becomes a continuous carpet in 3–5 years.
Removal
Bulb-by-bulb excavation in spring, before seed-set. All plant material bagged and disposed of as controlled waste — composting and green-bin disposal re-establish the plant. Herbicide is partially effective on foliage but leaves the bulb largely intact.
Reviewed by
The survey team
PCA-certificated surveyors, Japanese Knotweed Elimination
PA1 / PA6A certificated surveyors who carry out the site visits, write the management plans and sign off the reports issued to lenders and solicitors.
Reviews the technical, legal and lender statements in this article.
What this page can't tell you
- Guidance is general. Identification, treatment choice and timescales can only be confirmed by a site visit — photographs alone are indicative.
- Lender and insurer requirements vary by institution and change over time. We state what is typically accepted, not what any named lender will accept on your case.
- Guarantee (IBG) eligibility depends on the plan chosen, the survey findings and the underwriter's acceptance. It is not automatic.
- Legal points summarise published law and guidance current at the review date. They are not legal advice.
Last reviewed · Questions on anything stated here: 07582 869979
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