Invasive neophytes

© Caroline Winklmair, Himalayan balsam.
Habitat: Wild river LechSide valleysAuwälderBrunnwässer

Invasive neophytes

What are invasive neophytes? What can I do?

Neophytes ("new plants") are alien plant species that were introduced to a new area by humans after the discovery of America (1492). This happened either intentionally (e.g. useful, medicinal, forestry or ornamental plants) or unintentionally (e.g. seeds in bird feed).

Neophytes are often presented as "things to be controlled". However, the term "neophyte" is basically a completely value-free one. In addition to the emotional discussions about the negative effects, it is often forgotten that highly valued species such as potato or horse chestnut also belong to the neophytes in this country.

A rule of thumb (Tens Rule) states that out of 1,000 introduced species, about 100 become wild and of these, in turn, only 10 become permanently established. Of the 10 established species, only 1 species becomes a "problem neophyte" with negative impacts. To distinguish problematic neophytes from unproblematic ones, the former are referred to as "invasive." Their "success strategies": - efficient reproduction - rapid growth - strong competitive power.

In North Tyrol we find about 2,300 plant species, of which about 500 belong to the neophytes. Of these 500 species, 15 are considered invasive. They can cause ecological, economic and/or health damage and thus high costs.

The costs caused by invasive alien species (IAS) in Europe are estimated to be at least 12.5 billion EUR per year!*


The negative effects vary depending on the neophyte species and cannot be generalized. Invasive neophytes are generally a threat to health, economy and/or nature!

Glandulartouch-me-not(Impatiens glandulifera):

  • Weak or missing root penetration (plant death in autumn) " Soil erosion
  • Covering the soil with dead plants " Impeded germination of native plants.
  • Areal distribution (dominant stands) " Impoverishment of the accompanying vegetation due to light deprivation
  • High nectar production " Reduced pollination of native plants

Giant hogweed(Heracleum mantegazzianum):

  • Plant sap with ingredients harmful to health " Burn-like damage to the skin on contact and in combination with sunlight.
  • Area-wide spread (dominance stands) " Displacement of native plants and the native animals adapted to them.
  • Death of above-ground plant parts in autumn " Erosion on the "open" (vegetation-free) soils.

Canada goldenrod(Solidago canadensis), late goldenrod(S. gigantea):

  • Effective shoot growth (dominance stands) " Decrease in native species diversity.
  • Release of substances to the soil " Suppression of native species.
  • Low nutritional value of pollen and nectar " Endangerment especially of wild bees
  • Shallow rhizome network close to the surface " Soil erosion

Japanese knotweed(Fallopia japonica), Sakhalin knotweed(F. sachalinensis), bastard knotweed(F. x bohemica):

  • Strong lay and thickness growth of the rhizome (explosive effect) " Damage to buildings, walls, roads, etc.
  • Great fragility of the rhizome " On streams: Erosion on riparian areas
  • Areal distribution (dominant stands) " Habitat modification
  • Death of above-ground plant parts in autumn " Erosion on the "open" (vegetation-free) soils.

What can I do?

Intact nature means quality of life. Let's contribute together to the preservation of our native diversity and our health!

  • Tell your acquaintances!
  • Plant Do not plant invasive neophytes in your garden!
  • Replace invasive neophytes in your garden with native plants!
  • Remove invasive neophytes on your property!
    • "Wehret den Anfängen" - react as early as possible, because with passing time the negative effects as well as the difficulties of the fight increase!
    • Appropriate measure: Choose the method depending on the plant species, the stage of development of the plant and the area and density of the stand -. think also consider the protection of amphibians, reptiles, birds (ground nesting birds) and small mammals!
    • Right time or space: Prevent a seed formation!
    • Continuous success checks and re-treatments over several years if necessary - seed "stock" in the soil, etc.
    • Possibly subsequent maintenance of the site (e.g. sowing of site-appropriate seed mixture, planting of site-appropriate woody plants).
  • Avoid a spread of invasive neophytes, because "Prevention is better than aftercare"!
    • Note: Soil, seeds, bird feed etc. may contain seeds and/or rhizome fragments!
    • Dispose your garden waste properly and not in the open countryside!
  • Report Locations of invasive neophytes (as detailed as possible and with photo)!
  • Contact to the expert if you have any questions!

* Institute for European Environmental Policy, Technical support to EU strategy on invasive alien species (IAS). August 2009.


Tyrolean Lech Nature Park
Klimm 2, A-6644 Elmen
Phone: +43 676 9780136 or +43 664 4168466

Neophyte Competence Center Tyrol
Dr. Konrad Pagitz
University of Innsbruck, Institute of Botany
Sternwartestraße 15, A-6020 Innsbruck
Phone: +43 512 507 51059

Caroline Winklmair_Springweed bloom_Drüssige Springwort
© Caroline-Winklmair. Canada goldenrod (yellow), Japanese knotweed, giant hogweed, glandular knapweed.

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