(white) swallow wort

Seeds with a quiff

The dogbane family is represented in the Netherlands by only three genera – apart from the well known periwinkle (Vinca), of which the lesser periwinkle can be found in the wild in the woods in Limburg, there is swallow-wort (Vincetoxicum) and the naturalised common milkweed (Asclepias syriaca). The corolla of the swallow-wort is composed of five petals and on the outside of the anthers there are appendages that grow together to form a five piece crown.

The white swallow-wort can become 30 cm to around 1 m in height and has entire margined, oval to lance-shaped leaves. In the summer it produces small, white flowers. After flowering it produces up to 6 cm long fruit called a follicle. Each seed has a quiff, a dense turf of white hair.

As its Latin name (antidote) suggests, the plant was used in the past to induce vomiting to expel poison. The black swallow-wort (that has appeared recently in the Dutch dunes) was used as an antidote to snake bites.

Ecology and habitat

White swallow-wort really only occurs in Zuid-Limburg and the bordering river areas (also between stones) but more recently also in dunes. This species prefers dry, calcareous rich soils, often on the edge of bushes.

Threat

This rare plant is considered to be ‘vulnerable’ according to the Red List because the number of individuals (less than 50) and habitats (less than 10) are both very low. Its rarity is due in part to the fact that the Netherlands is on the edge of its natural distribution.