Large herb, up to 3 m, and quadrangular stems, frequently reddish, and with black berries.
Scientific name: Phytolacca americana L.
Common names: pokeweed, American pokeweed, pokeberry
Status in Portugal: invasive species
Risk Assessment score: (in development)
Synonymy: Phytolacca decandra L., Phytolacca vulgaris Crantz
Last update: 11/07/2014
How to recognise it
Large herb up to 3 m, ramified, sometimes woody on the base. Quadrangular stems, green, red or purple.
Fruits: purple-black berries, composed of 10 fused segments in a ring, making the stem hang in maturation.
Flowering: May to December.
Phytolacca heterotepala Walter, also exotic, and normally found in the surroundings of Coimbra and Lisbon, is similar but it is a shrub (or a small shrub) and it presents unequal tepals (the exterior narrower that the rest) and more stamens (9-21).
Characteristics that aid invasion
It propagates by seed, producing more seeds which are dispersed by birds.
It also propagates vegetatively by sprouts from the roots.
Native distribution area
Distribution in Portugal
Mainland Portugal (Minho, Trás-os-Montes, Douro Litoral, Beira Litoral, Beira Alta, Beira Baixa, Estremadura, Ribatejo, Alto Alentejo, Algarve), Azores archipelago (all islands), Madeira archipelago (Madeira island).
Other places where the species is invasive
Invasive in several European countries, western USA (California).
For medicinal purposes and use in dyeing.
Preferential invasion environments
Ruderal and disturbed habitats, crop fields and roadsides. It also invades semi-natural habitats.
Impacts on ecossystems
It inhibits the development of native vegetation.
It has allelopathic effects, inhibiting the development of other species.
It causes important damages in agricultural areas.
Some parts of the plant (stems, leaves, fruits) are toxic, being noxious for animals.
Controlling an invasive species demands a well-planned management, which includes the determination of the invaded area, identifying the causes of invasion, assessing the impacts, defining the intervention priorities, selecting the adequate control methodologies and their application. Afterwards it is fundamental to monitor the efficiency of the methodologies and recuperation of the intervened area as to perform, whenever necessary, the follow-up control.
The control methodologies used for Phytolacca americana include:
Hand pulling (preferencial methodology). In more compacted substrates, hand pulling must be made during the rainy as to facilitate the removal of the root system. As much as possible, it should be guaranteed that there are no large roots left in the ground.
Visit the webpage How to Control for additional and more detailed information about the correct application of these methodologies.
DAISIE European Invasive Alien Species Gateway (2012) Phytolacca americana. Available: http://www.europe-aliens.org/speciesFactsheet.do?speciesId=8642 [Retrieved 10/11/2012].
Dufour-Dror J-M (2012) Alien invasive plants in Israel. The Middle East Nature Conservation Promotion Association, Ahva, Jerusalem, 213pp.
Fagundes D, Az J, Beiras MB (2007) Plantas invasoras de Galicia. Bioloxía, distribución e métodos de control. Xunta de Galicia, Santiago de Compostela, 209pp.
Marchante E, Freitas H, Marchante H (2008) Guia prático para a identificação de plantas invasoras de Portugal Continental. Imprensa da Universidade de Coimbra, Coimbra, 183pp.
Silva L, Corvelo R, Moura M, Land EO, Jardim R (2008) Phytolacca americana L. In: Silva L, Land EO, Luengo JLR (eds) Flora e fauna terrestre invasora na Macaronésia. Top 100 nos Açores, Madeira e Canárias. Arena, Ponta Delgada, pp. 370-372.
USDA, NRCS. (2012) The PLANTS Database. National Plant Data Team, Greensboro, NC 27401-4901 USA. Available: http://plants.usda.gov [Retrieved 10/11/2012].
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