The Key lime tree (Citrus aurantifolia Swingle), also popularly known as the Mexican algae or West Indian lime, is precious across U.S. Department of Agriculture plant hardiness zones 9 through 11 as an ornamental because of its kind, foliage and blossoms, in addition to for the little, acidic fruits it produces.
Habit, Form and Hardiness
The Key lime tree is an evergreen, meaning it keeps its foliage year-round. This plant grows very vigorously, reaching a mature height of 6 1/2 to 13 feet. Key lime trees possess lots of slender, spreading branches, appearing bushy with a curved, umbrella or vase-like canopy shape. The Key lime is vulnerable to cold damage, suffering injury to foliage below 32 degrees Fahrenheit and timber damage or death if temperatures drop below 29 degrees Fahrenheit.
Foliage and Bark
The evergreen leaves of this Key lime are mild purplish when young and dull dark-green when mature. These leathery, elliptical leaves measure 2 to 3 inches long with little, curved teeth. The foliage grows densely and has a pleasant scent. The slender branches of the majority of Essential lime trees have lots of sharp 3/8-inch long spines. There are a number of spineless cultivars; those selections produce less fruit, have darker green foliage and are more streamlined.
Flowers and Fruit
Key lime tree blossoms, appearing on the plant in spring, are faintly fragrant, white and measure 2 inches across. The key lime fruit that develops from these flowers is born singly or in clusters and is around or slightly elliptical and sometimes has a small nipple at the same end. The fruits generally have a diameter of 1 1/2 to 2 inches and have a thin peel that is greenish yellow to yellow in maturity. The greenish yellow pulp is juicy, acidic and split into 10 to 12 segments.
Site Preferences and Applications
The Key lime tree performs best if planted in full sunlight and at least 12 to 20 feet away from structures and other trees. It may grow well in a range of soils, including sites that are highly alkaline or acidic. Good soil drainage is very important to Key lime tree growth; nutrient deficiencies and disorders can occur where excessive moisture lasts around the plant’s root system. The Key lime tree can be planted as a specimen, utilized as a screen or hedge or espaliered.
Recently planted Key lime trees require watering at planting, every other day for about a week, after which one or two times per week for the first two or three months following planting. Once shown, only occasional watering during prolonged dry periods is warranted. Occasional, though not excessive application of a balanced fertilizer will encourage Vital lime tree vigor. A paling or mottling of leaves may indicate a nutrient deficiency. Excessive fertilizer can stimulate a feeling of new growth especially vulnerable to pests and diseases. A light pruning to thin out the canopy and remove problematic crossing or rubbing branches is best done soon after fruit harvest.