Though the cranberry is a creeping or prostrate shrub, plants can intertwine and dominate parts of a bog. The leaves, which are evergreen, are leathery with whitish undersides. Cranberry blossoms in June or early July. The pinkish petals curve back, sort of like a cartoon drawing of an exploded gun barrel. Cranberries ripen in September and October but, as pointed out earlier, since berries persist through frosts, they can be picked into November or later.
Berries vary in size, from half to slightly larger than commercial size.
When ripe, they turn bright red. Cover and cook slowly until the fruit is tender, about 20 minutes. Cool slightly, then beat with a wire whip until fluffy and light. Let sauce cool to room temperature, about 1.2 hour. Cover and chill thoroughly.