Specimen plants are plants which are grown as exhibition pieces in the garden. They are typically isolated from other plants so that they stand out, rather than being situated in a mass of plantings. Specimen plants are one of the key aesthetic elements of the garden, and in some cases they can be decades or even hundreds of years old. In antique gardens, the specimen plants may include rare and unusual species, such as heritage roses and unique tree cultivars.
Many specimen plants are trees or large shrubs, for a number of reasons. Bigger plants tend to stand out and look appropriately scaled when they are planted alone in an open space, for starters, and they also tend to be more long-lived. Since a specimen plant is intended to be a permanent display piece, a plant with longevity is desired so that the plant will stay healthy for years. Large plants can also be more showy, with features like bright flowers, unusual foliage, peculiar twists and turnings of their branches, and so forth.