In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.
There are many different kinds of evergreen plants, both trees and shrubs. Evergreens include:
An additional special case exists in Welwitschia, an African gymnosperm plant that produces only two leaves, which grow continuously throughout the plant's life but gradually wear away at the apex, giving 20–40 years' persistence of leaf tissue.
Leaf persistence in evergreen plants varies from a few months (with new leaves constantly being grown as old ones are shed) to several decades (over thirty years in the Great Basin Bristlecone Pine).