Apocynaceae: a twining long-lived perennial to 70cm, with a stem that is erect, stout and glabrous. Found on cliffs and slopes, especially in calcareous soils. Flowers in whorls form a raceme, flowers are 1cm across, with five white petals, and sharp-pointed sepals. Blooming from June-July. Fruits reach a length of about 5cm and contain many seeds showing a tuft of white hairs. The leaves are opposite, ovate to lanceolate and short-stalked. Native to continental Eurasia (including some Baltic islands). It is not present in Great Britain and Ireland. There are introduced populations in North America (Ontario, Michigan, and New York).
Vincetoxicum hirundinaria is a venomous plant traditionally used in treating diseases and in magic. The plant was mentioned by Pedanius Dioscorides as a traditional plant used by Dacians and known as "ZOO-USTE", the "herb of animals", believed to open any locked door.
NOTE: some literature state that this plant is poisonous.
About 1/3 germinate without treatment or use GA-3 or 8 weeks prechill to germinate in 1-3 weeks. When they are large enough to handle, prick out the seedlings into individual pots and grow them on in a lightly shaded position in the greenhouse for at least their first winter. Succeeds in ordinary garden soil, in full sun or part shade.