Abstract
Seed and seedling traits of three congeneric alien species in Europe, differing in their region of origin, invasion status and history (Impatiens glandulifera, I. parviflora, I. capensis), were compared with the native I. noli-tangere in the laboratory and common garden experiments. Differences in the invasiveness of three alien species of balsams in the temperate zone of Central Europe can be attributed, at least in part, to their differing performances in the early stages of their life cycle.
The short period of time required for seed stratification and the high seedling biomass of I. glandulifera might have increased its invasion potential compared to other Impatiens species occurring in the Czech Republic. The absence of I. capensis, a successful invader in several European countries, from the Czech flora may be due to a low propagule pressure.