- Happen
- species delineation
- risk potential
- public spaces
- Giant hogweed on private property
- frequently asked Questions

Information about the obligation to report giant bear hogs is circulating, especially on the Internet. Giant hogweed is a dangerous plant that causes phototoxic reactions. There is no obligation to report Riesenbärenklau.
In a nutshell
- Occurrence: in damp areas
- phototoxic reaction upon contact with the plant sap
- there is none obligation to report
- in the event of sightings in public spaces, it is advisable to report to the responsible municipality
- on private property you must remove the plants yourself
Happen
The giant hogweed (Heracleum mantegazzianum) grows in sunny to partially shaded locations. The giant hogweed can grow very tall, especially in partial shade, as it literally grows towards the sun. The soil should always be moderately moist.

The Giant Bear Claw can often be found in the following locations:
- creek/river bank
- lakeside
- moderately wet swamp areas
- moderately wet ditches
species delineation
In Central Europe there are a few other Bear Claw species. The most common species are the meadow hogweed (Heracleum sphondylium), which is native, and the Austrian hogweed (Heracleum austriacum). This does not only occur in Austria, but can also be found in Germany, especially in the southern federal states.
Identifying features of the giant hogweed:
- reddish spots on the stem
- Stem has little to no angular grooves
- Stem is sparsely to slightly bristly hairy

Notice: Occasionally it can happen that other Bärenklau species also have reddish spots. It has not yet been fully clarified whether this is a crossbreed or the formation of anthocyanins as sun protection.
risk potential
The giant hogweed has a very high concentration of so-called furanocoumarins. This ingredient on the skin in combination with UV radiation triggers a phototoxic reaction that resembles a burn.
Not only the giant hogweed can cause a phototoxic reaction, the ingredient is present in all umbelliferae in more or less high concentrations. Sensitive people can also react with dermatitis when they come into contact with the plant sap of other hogweed species.
On very hot days you should also not stand under a giant hogweed. When it is very hot, it secretes essential oils through the leaves, which can cause allergic reactions in sensitive people, for example in the form of shortness of breath.
public spaces
There is none official reporting obligation for the giant bear hog. However, if you discover a plant in public space, it is advisable to report the giant hogweed to the local municipality, for example to the environmental agency. It can happen that children or dogs seriously injure themselves when they come into contact with the plants.

In public areas, the municipalities usually take care of the disposal of the plants. This must be done by professionals. A protective suit must be worn for removal and feet, hands, eyes or face must be completely covered. This prevents the sap from getting on the skin.
The plants must be removed including the roots. To prevent the giant hogweed from appearing again, a herbicide is occasionally applied to the spot.
Giant hogweed on private property
Because it none There is an obligation to report giant hogweed, you do not have to do this on private property either. If you want to get rid of the giant hogweed on your property, you should also leave the disposal to a professional. Occasionally you can contact the local fire brigade, who will take on this task for a donation.
As a rule, however, the disposal of the giant bear's hogweed is subject to a fee. Therefore, you should remove the plants as soon as they appear. The seeds can survive in the soil for over 100 years. Young plants can usually be completely removed from the soil without any risk.
Removal Tips:
- Put the garbage bag over the plant
- cover skin
- wear safety glasses
- Deeply expose the root
- then cover the soil with weed film
frequently asked Questions
What do I do if I come into contact with the plant sap?Immediately wash the area with water and then cover. If you come into contact with the giant hogweed over a large area, you should consult a doctor immediately.
How do I dispose of giant hogweed?Put the excavated giant hogweed in a garbage bag and dispose of it in the residual waste.
How tall does the giant Bärenklau get?On average, the giant Bärenklau grows up to three meters high. However, there were isolated specimens that were more than 3.5 meters high.