Japanese Rose (Rosa rugosa): its invasion and colonisation of the Sefton Coast, north Merseyside, UK

Abstract

A spiny shrub native to north-west Pacific coasts, Rosa rugosa Thunb. (Japanese Rose) was introduced into Britain in the 19^th century as a garden plant. It has since become a well-established and widespread naturalised alien, especially on sand-dunes, shingle beaches and other dry coastal habitats. The plant is also considered invasive on coasts of many other countries in Northwest Europe. Mounting concern about its recent spread on the internationally important sand-dune system of the Sefton Coast, north Merseyside, led to a volunteer survey being organised in 2014, involving 47 participants. They searched most of the 27 km-long coastal zone, recording almost 500 patches with a total area of nearly 6 ha. R. rugosa occurred especially on younger calcareous dunes (soil pH 5.6 – 8.2) near the sea and close to roads and human habitation. Few patches were found on older, more acidic duneland, or on a 5 km erosion front around Formby Point. This pattern of occurrence accords with that reported elsewhere for R. rugosa, indicating that the sea is implicated in the dispersion of propagules and that the species also establishes from anthropogenic sources, including ornamental plantings. It is concluded that the plant is a threat to dune habitats and species on the Sefton Coast. Control measures are discussed and the early stages of patch removal are described.