Gauja National Park
Giant hogweed (Heracleum sosnowskyi) originated in the Caucasus region and was brought to Latvia as a fodder plant. It has become widespread not only in open areas, but also on roadsides, forest edges, and along waterways, via which the Giant hogweed is able to effectively distribute its seeds over a wide area. The spread of this species threatens native plants and their habitats, causing economic damage, damage to the environment and to human health.
A perennial plant 2-3 metres in height with a leaf which can be up to 1,5 m long and visually resembles the leaves of a rhubarb plant. Most often the leaves are separeated in three sections and rounded. The diameter of the stem can reach 10 cm.
The flowers and a white or faint pink colour with a tint of yellow or green. The flowers are arranged in a slightly curved cluster, up to 50 cm in diameter. The cluster can contain up to 100 thousand flowers. The stems of the whole cluster and the composite of clusters within are coarse with short hairs. Blooms from June to August. Seeds have an elliptical form ~ 1 cm in length.
Heracleum mantegazzianum Sommier et Levier and Heracleum Persicum Desf. All three species are invasive in Latvia and all cause severe burns when exposed to the skin.
Giant hogweed is rich in photodrynamically active substances – furocoumarins, which, when exposed to the skin, cause severe burns under the influence of the sun’s ultraviolet rays.
Manner of introduction
Introduced as a promising fodder plant.
Characteristics of growing conditions
Widely distributed on abandoned land areas, in anthropogenically affected habitats, areas of shrubs, sparse forest, along roadsides, in ditches and along rivers and other types of water bodies.
Familiarize yourself with invasive species and submit your observataions to: “Invazīvo sugu pārvaldnieks”!
Source: “Invazīvo sugu pārvaldnieks”, Nature Conservation Agency