First observation in the wild:	1893
Invasion stage:	spread
Spatial distribution:	widespread

Reproduction in the wild:	yes
Dispersion potential:	high
Natural habitats:	high

More on invasiveness: The taxonomic status of Helianthus tuberosus forms established in the wild is uncertain and could differ from the cultivated form of H. tuberosus (see discussion in Balogh 2008). This "wild form" prefers well-lit, sandy, moist and nutrient-rich soils. It grows best in habitats repeatedly disturbed by floods (riparian areas) and is tolerant of a few weeks of flooding. It may also occur in ruderal and agricultural environments. In Belgian climatic conditions, the plant doesn't produce viable seeds and propagates vegetatively. Tubers and pieces of rhizomes are transported with rodents and flowing water, especially winter floods. It is in strong expansion in neighbouring countries, especially in France, Germany and Switzerland.

Predation / Herbivory:	low
Competition:	high
Disease transmission:	low
Genetic effects:	low

Nutrient cycling:	unknown
Physical alteration:	high
Natural successions:	high
Food web alteration:	low

More on impacts: The plant produces dense and persistent monospecific populations along rivers, where it outcompetes native species, slows down natural colonisation by trees and favours river bank erosion. Helianthus produces phytotoxic compounds and can be as competitive as Fallopia japonica in alluvial habitats. It can be a weed of agricultural fields either by invading fields or reducing the yield of consecutive crops (e.g. sugarbeet and maize).

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