shoot showing three successive years of retained leaves]]In botany, an evergreen plant is a plant that has leaves all year round. This contrasts with deciduous plants, which completely lose all their foliage for part of the year. Leaf persistence in evergreen plants may vary from only a few months (with new leaves constantly being grown and old ones shed), up to a maximum of 5 years in Great Basin Bristlecone Pine Pinus longaeva Ewers, F. W. & Schmid, R. (1981). Longevity of needle fascicles of Pinus longaeva (Bristlecone Pine) and other North American pines. Oecologia 51: 107-115.. However, very few species show leaf persistence of over 5 years. in winter]]One additional special case exists in Welwitschia, an African gymnosperm plant which produces only two leaves, which grow continuously throughout the plant's life but gradually wear away at the apex, giving about 20?40 years' persistence of leaf t