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

Philip Howard Smith,Ben Deed

doi:10.33928/bib.2019.01.185

Abstract

A spiny shrub native to north-west Pacific coasts, Rosa rugosa Thunb. (Japanese Rose) was introduced into Britain in the 19th 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.

Highlights

Origin and geographical distribution Rosa rugosa Thunb. (Japanese Rose) is a deciduous, spiny, strongly suckering shrub native to northern Japan, north-east China and the Russian far-east
The Botanical Society of Britain & Ireland (BSBI) Maps Project shows an exponential rate of spread (Fig. 1), though some of this increase is thought to be due to better recording (Maskew, 2002)
Partly because of the varied abilities of the participants, collection of supporting ecological information was limited and recommendations for habitat recording were sometimes misconstrued. Another shortcoming was the exclusion of the golf courses which occupy about 25% of the dune system (Smith, 2009), though R. rugosa is not thought to have a strong representation on these land-holdings

Summary

Introduction

Origin and geographical distribution Rosa rugosa Thunb. (Japanese Rose) is a deciduous, spiny, strongly suckering shrub native to northern Japan, north-east China and the Russian far-east. The shrub was first recorded in the wild in Cumberland in 1927 (Maskew, 2002), since when it has become a well-established naturalised alien throughout Britain and in parts of Ireland. The Botanical Society of Britain & Ireland (BSBI) Maps Project shows an exponential rate of spread (Fig. 1), though some of this increase is thought to be due to better recording (Maskew, 2002). By 2014, R. rugosa had been observed in 1325 hectads (10 x 10 km UK National Grid squares) in Britain and Ireland. The plant is naturalised in large parts of northwest and central Europe, being considered invasive along coasts of the North Atlantic, North Sea and Baltic, including the Netherlands, Germany, Denmark, Norway, Sweden and Lithuania (Bruun, 2005; Weidema, 2006). Infestations have been reported in dunes on the Atlantic coasts of Canada (Hill et al 2010)

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