Citrus x aurantiifolia

Key lime is a vigorous large shrub or small tree in the Rutaceae family that is best known for its green to yellow (when ripe) fruit that is very juicy and aromatic. It is native to the tropical regions of southeastern Asia, such as Malaysia and Indonesia but it has been carried and cultivated throughout the tropical regions of the world.  It was cultivated commercially in the Florida Keys in the 19th century, hence its common name that is still used today although there is little key lime production remaining in Florida.  Key lime has glossy elliptical to oblong evergreen leaves, similar to the leaves of the orange tree.  Therefore, its name comes from the Latin noun aurantium, meaning "of orange" and folia which means "leaves."

Key lime should be planted in the warmest possible location in your landscape, protected from cold winds and in full sun, as it does not tolerate shade.  It will not survive outdoors in the winter in colder climates and will struggle to produce fruit.  The plant grows best in light to medium textured soils that are aerated and have good drainage. The plant will not do well in heavy clay soil or soils that drain poorly.  The plant does not tolerate standing water or flooding. The plant prefers a pH range of 5 to 8 and is sensitive to high salinity. It is very drought tolerant once established.  Do not overwater.  Key lime should be fertilized sparingly. Pruning is only required to shape it, remove dead wood, limit plant size, or thin fruit. It can be grown as an espalier or as a hedge.  There are several different methods for propagation including seeds, root cutting, grafting or layering. 

All parts of the leaves and fruit are used for cosmetic, medicinal and edible uses.  The flowers are showy and fragrant.  The leaves are fragrant when crushed.

Plant outside in full sun for year-round enjoyment in tropical or subtropical climates or put in a planter for movement inside when the weather turns cold.

Insects, Diseases and Other Plant Problems:  Key lime is highly susceptible to lime anthracnose (also called withertip and blossom blight).  Overwatering may cause fungal infections or root rot and the tree to decline in fruit bearing.  Key lime trees in the home landscape are susceptible to trunk injury caused by lawn mowers and weed whackers.

The Clemson Cooperative Extension Home and Garden Information Center has a factsheet on common citrus insect and related pests.