Monograph of invasive plants in Europe N°6: Asclepias syriaca L

ABSTRACT This work synthesizes all aspects of Asclepias syriaca L. (Apocynaceae) including the taxonomy, distribution, history of introduction and spread, ecology, biology, uses and benefits, impacts on biodiversity and agriculture, legislation, and management. Asclepias syriaca is a perennial broad-leaved species native to North America. Introduced for ornamental and various other purposes, such as a source of fibre and rubber, it has become established in many regions of Europe and it had increasingly spread in the last decades (>1980s). Its reproductive behavior is characterized by a high production of wind-dispersed seeds and by the propagation of creeping lateral rhizomes, which allows the species to proliferate rapidly. The species persists in a wide range of edaphic and climatic environments. It occurs particularly in anthropogenic and (semi-)natural habitats, such as roadsides, agricultural land, abandoned sites and grasslands, open shrubland, and forests, respectively. Studies have demonstrated negative impacts on the biodiversity and ecosystem processes in invaded regions, namely in open sand grasslands in Hungary. Asclepias syriaca occurs as a competitive weed in crop fields. Since 2017, the species is regulated by the European Union (EU) under the Regulation No. 1143/2014, which states that A. syriaca is subjected to restrictions such as a ban on importing, selling, breeding and that EU member states are required to place effective management measures. Awareness raising activities are important to inform the public, farmers and stakeholders about the risks of this invasive alien plant. Effective direct control options include mechanical control as well as herbicide application.