Japanese knotweed · Dublin
Japanese knotweed in Dublin: 341 public records
Public biodiversity records hold 341 Japanese knotweed sightings for Dublin, the latest from 2023. A record near the house is a mortgage question, not a gardening one.
341
Japanese knotweed records in Dublin (GBIF / NBDC)
309
giant hogweed records
2023
most recent record year
Knotweed in Dublin
Japanese knotweed spreads along rivers and railways and from dumped garden waste. It goes three metres down and seven metres out, comes up through tarmac and drains, and a piece the size of a fingernail regrows. In Dublin, public biodiversity records (via GBIF, mainly the National Biodiversity Data Centre) hold 341 knotweed sightings. Counts depend on who was recording: a county with an active recorder scores high.
Records within 2 km of town centres, for the towns we hold detail on:
| Rathmines | 104 records |
| Ranelagh | 102 records |
| Donnybrook | 94 records |
| Rathgar | 81 records |
| Ballsbridge | 69 records |
| Sandymount | 63 records |
| Dublin 7 | 63 records |
| Churchtown | 63 records |
| Harolds Cross | 56 records |
| Drimnagh | 52 records |
| Glasnevin | 51 records |
| Dublin 8 | 49 records |
For a house, what matters is a record within about 250 m, and the lane or stream behind the garden. Walk the boundary at a viewing; the stems are hollow, bamboo-like, with red speckles, and the leaves are shield-shaped.
Check one house in Dublin
The area tells you the odds. The report tells you about the house.
Enter the Eircode. The free snapshot shows which of the twenty-nine checks flag up. The full report (€24.99, one house, no account) lists knotweed and giant hogweed records within 250 m of the house with year and distance, and tells you what to ask the seller in writing.
Or read the sample report first: a real house, 16 pages.
Other checks for Dublin
- Flood risk in Dublin: 4,709 recorded events around 276 towns
- Radon in Dublin: 17 of 278 towns in a High Radon Area
- BER in Dublin: 11% of homes rated E to G
Dublin is in the pyrite belt. Houses built roughly 1997 to 2013 with hardcore from the affected quarries may have heave in floors; the Pyrite Resolution Board ran the remediation scheme. The report flags the build years and the scheme for the exact house.
Other counties
Questions people ask
- How common is Japanese knotweed in Dublin?
- The National Biodiversity Data Centre and other recorders have logged 341 knotweed records in Dublin (650 including giant hogweed), the latest in 2023. Records cluster along rivers, railway lines and roadsides, and reflect where people record as much as where the plant grows.
- Will a bank lend on a house with knotweed?
- Irish lenders have no blanket rule, but valuers now note it, and where it is within seven metres of the house they may ask for a management plan or knock the valuation. UK lenders decline outright. Ask the seller in writing whether it is or was on the property and for treatment records.
- What does it cost to deal with?
- Herbicide treatment runs three to five seasons at a few hundred euro a year for a small stand. Excavation and licensed disposal for a large stand runs into five figures. Never cut it and put it in the green bin: a fragment regrows.
Sources
- GBIF occurrence records for Ireland (National Biodiversity Data Centre and others)
- Invasives.ie: identification
Area figures, compiled from public records. They describe the town or county, not any one house. The paid report checks the exact Eircode.