An evergreen plant means that the leaves or foliage remain on the plant for as long as it lives, through all seasons. The leaves do not drop off in the autumn as with deciduous plants. Evergreen can relate to any type of plant regardless of size - small alpines, indoor plants, perennials, shrubs and trees. In the latter case, conifer trees are generally evergreen, though there are also a few that are deciduous.
It is also possible for some plants to be classes as semi-evergreen, in which case - shrubs in particular, lose part of their foliage in late autumn or winter. This is generally to allow room for new leaves to form. This should not be confused with a true evergreen shedding some of its older leaves in spring as the new foliage starts to grow.
In the case of true evergreen plants, the older leaves are dropped to make room for the new growth – often in spring or early summer. The old leaves are not dropped until the new leaves have formed, so to all intents the plant is always covered with foliage.
Variegated evergreen foliage on Elaeagnus 'Frederici' | Evergreen perennial Penstemon | Evergreen flowering shrub - Daphne
It is sometimes wrongly thought, that evergreens only have green leaves. Not so, for there are many shrubs in particular that are truly evergreen, but have brightly coloured leaves, sometimes gold, purple, silver, or variegated.
Many plants are evergreen in their native habitats, such as south East Asia, but when grown in temperate regions, will lose their leaves in the winter.
In general conversation, evergreen sometimes refers to long-lasting – such as some songs – or even persons. Many garden plants – perennials, shrubs and trees live for several years. This does not make them evergreen in the horticultural sense, for a wide range of long-lived plants lose their leaves in the autumn and are therefore classed as deciduous.
Evergreen shrubs and trees are invaluable for year-round interest in the garden, as well as being useful for groundcover, screening and privacy. Most of the evergreen plants in the garden are also flowering plants – an exclusion being the evergreen ferns. If you are seeking all-year interest in your garden then evergreens should be high on your list of priorities for planting.