American pokeweed
Pyhtolacca americana L.
Appearance
The species can grow up to 250 cm tall and is branched in the upper third. The leaves are up to 25 cm long and ovate. The shoots are often reddish. The drooping inflorescences are characteristic. Each flower may form a fruit divided into ten chambers, with one 2 to 3 mm seed per chamber. The fruits are first green, later dark red to black.
Distribution
American pokeweed is originally from North America and it was introduced as an ornamental and dyeing plant. The species occurs feral mainly in southern Styria and eastern Lower Austria (Weinviertel and Marchfeld), prefers open, disturbed habitats and grows especially on forest edges, clearings and woodlots. Very rarely, arable land is also infested.
Spread
American pokeweed is a perennial turnip geophyte, which means it survives as a turnip in the soil. The plant lays adventitious buds from which numerous new shoots sprout in the spring (early April). The species also reproduces by seeds, which are eaten by birds and spread over long distances.
Economic importance
The American pokeweed can form pure stands and displacement effects towards the native flora are therefore possible. The species is particularly problematic in sparse, often species-rich forests, where it finds good development conditions.
Prevention and control
- Emerging populations must be located and contained as quickly as possible.
- Preventing seed production is critical because further spread of pokeweed relies heavily on successful seed production and dispersal.
- Very small populations and single individuals can be removed by hand (digging, spading the beet)
- Information on herbicide efficacy is scarce. For example, glyphosate and vigor herbicides such as 2,4-D and dicamba had a suppressive effect (> 80% efficacy) in experimental studies (see list of plant protection products approved in Austria).
Last updated: 17.12.2021
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