Maßnahmen gegen Nichtheimische, gebietsfremde und invasive Tiere und Pflanzen Informationserteilung

A biennial to perennial herbaceous plant that flowers from July to September - the so-called Herculean perennial, which is not a herbaceous perennial, also known as giant hogweed. Region of origin: Caucasus. Due to its size (up to 3.50 m) and the large white umbel, it is beautiful to look at, but also poisonous. The perennial with the white umbel flowers has been spreading rapidly for several decades. It finds good conditions on fallow land and along riverbanks. One plant reproduces with up to 50,000 seeds, which can germinate for up to 10 years. The light and buoyant seeds spread along waterways, roads and railways. In order to consistently suppress the plant, it is also necessary to combat populations on private land, as they can otherwise spread again from there. The help of citizens is therefore required and an appeal is made to the owners of affected private property to take on the removal of the giant hogweed.

Precaution:

• Avoiding spreading (garden waste, beekeepers, etc.) and limiting the spread (watercourses, compost waste, etc.)
• Education and information (flyers, training)

Protective measures:

The following measures must be observed when combating giant hogweed in order to prevent adverse health effects:

• Protective clothing is essential (gloves, protective clothing, goggles and respiratory protection if necessary).
• If possible, remove plants when it is overcast, rainy and only lightly windy or at dusk.
• Face and hands should also be protected with sun cream with a high sun protection factor.
• Avoid confusion with other plant species (ore angelica) (nature conservation authority).

Control methods:

The control of Hercules perennial is lengthy and labor-intensive. For this reason, control outside your own garden should be carried out at local authority level together with specialists. The following control options are available:

• Weeding seedlings in early spring, young plants in spring/autumn
• Milling or plowing the plants in spring, when growth is just beginning, and pulling out the rhizomes
• Cutting off the uppermost rootstock with a sharp spade approx. 15 cm below the soil surface in early spring (until April) and in the fall
• Cut off the seed heads before the seeds ripen from mid-July (beware of plant sap splashes). The seeds must be prevented from falling off as they will continue to ripen. Death of the mother plant from fall
• Grazing: short-term by pigs (also fresense roots, small stands), perennial with sheep, goats and dark-skinned breeds for larger stands

Recommended under certain conditions:

• Digging up individual plants (up to 200 specimens) in spring
• Cut off inflorescences during full flowering (too early leads to new growth)
• Mowing: Mowing the plants (height 0.5 - 1 m) is suitable for larger contiguous areas. This is best started shortly before flowering. This is when the plant is weakened the most. However, mowing, once started, must be repeated approx. 6 - 8 times per year at the beginning and during flowering or 5 - 6 times every 10 days, as the species produces flowers again just 14 days after mowing, sometimes at a height of less than 10 cm.

Not recommended:

• Herbicide applications and other chemicals: major risks due to environmental effects (accompanying flora, amphibians, people in the vicinity, run-off into bodies of water, etc.).

Control:

• Permanent removal also includes multi-year follow-up checks from spring onwards, as the seed may still be in the soil and only germinate years later. Combined methods as described under control. Dense swards prevent the seeds lying on the ground from germinating.

Disposal:

• Commercial composting, especially of cones and whole plants
• Commercial incineration, especially of cones and whole plants

All parts of the Hercules plant contain a phototoxic substance, furanocoumarin, which gets onto the skin on contact with the plant sap. When exposed to sunlight and subsequent irradiation with UV-A, furanocoumarin forms an antigen together with the body's own protein, which leads to a strong allergic reaction. Mild reactions are itching, redness, swelling, more severe reactions are fever, sweating, circulatory shock and blistering, reminiscent of a severe burn (1st to 2nd degree) and a discoloration that can last for weeks (photodermatitis). (cf. Kowarik 2003). Even dried stems, flowers and seeds still contain active furanocoumarin. The tricky thing is that there is no visible reaction immediately after contact. The greatest risk of exposure to sunlight occurs half an hour to 2 hours after skin contact.

What should you do if you come into contact with the Hercules plant?

If you have touched the Hercules perennial or suspect that you have done so, you should avoid the sun immediately. Even if no reaction is visible, the affected areas should be washed thoroughly with soap and water, or better still with alcohol, and treated locally with creams and lotions containing glucocorticoids. It is advisable to apply sunscreen afterwards. The sun should also be avoided for the next 2 to 3 days.

Advice: Mecklenburg-Vorpommern State Office for the Environment, Nature Conservation and Geology
Implementation: Public order offices of the municipalities or local authorities