 Pumpkins are, however, rather hardy, and even if many leaves and portions of the vine are removed or damaged, the plant can very quickly re-grow secondary vines to replace what was removed.Pumpkins produce both a male and female flower; they must be fertilized, usually by bees.Pumpkins have historically been pollinated by the native squash bee "Peponapis pruinosa", but this bee has declined, probably at least in part to pesticide (imidacloprid) sensitivity.