Growing citrus trees can be one of the most rewarding experiences for a gardener. With its attractive evergreen leaves that remain intact for up to three years, wonderful smell, and the final reward of a tasteful bounty of fruit, a successful citrus tree is a source of pride in a garden or landscape.
Originally from China, oranges arrived in North America via Europe. The trees grow to around 25 feet in height with dark green leaves and small white flowers. Through extensive cultivation there are now of a large variety of orange trees to choose from. No matter which tree you choose, oranges are very vulnerable to cold temperatures and it is possible to lose an entire crop to frost overnight. Ideal daytime temperatures are 60 to 85 degrees F. Technically a berry, the fruit (or berry) tends to measure 2 to 4 inches, and the numbers of seeds contained vary by variety. Navels, the seedless variety, all originate from a single tree in Brazil that produced a mutated seedless orange in 1820. Via cuttings from the original tree, navels are now planted worldwide.
Popular varieties of oranges include Calamondin,
Satsuma, Valencia, and Navel.
Grapefruits originated in the Caribbean. Now grown worldwide, the attractive trees reach 25 to 30 feet in height. With long green leaves and a white flower, the fruit, like an orange, is actually a berry. Both sweet and bitter, the fruit is very acidic and traditionally bright yellow. A mutation which produced the red ruby variety was quickly patented in the early part of the 20th century and is now the most popular choice in North America. Seed content depends on the variety, but there are a few seedless choices. Like oranges and other citrus, freezing temperatures can kill or harm the fruit. However, grapefruits are considered the most hardy of the citrus fruits. Popular varieties include Duncan, Foster, Marsh, Oroblanco, Paradise, Navel, and Star Ruby.
The mandarin tree is a different class of orange. Smaller than typical orange trees, they can grow to 25 feet in height but more often top out around 20 feet. The fruit is a small version of an orange, but the flesh can peel away more easily and the taste is sweeter than that of an orange. Mandarins are hardier than most of the citrus world, with some varieties surviving temperatures as low as 4 degrees F. Popular varieties include Changsha, Clementine, Cleopatra, Dancy, Dweet, Fremont, Kincy, and Ponkan.
Originating in India, lemons arrived in North America via the Europe where they had been cultivated for centuries. The trees reach 30 feet at maturity and bear fruit that begins green then changes to yellow as it matures. Like other citrus, the fruit is actually a berry. When planted indoors, the tree can thrive in a pot for years but will not produce fruit. Take special care to avoid exposure to cold in outdoor plants. The Harvey variety is considered to be the best cold hardy lemon.
Popular varieties of lemons include Eureka,
Improved Meyers, Lisbon, and Harvey.
There are two popular varieties of lime, with the key lime (sometimes called the Mexican lime) leading the way. The Bearss is the other popular variety. Different from other citrus, limes grow on shrubbery reaching heights of only 10 feet on average. Like other citrus plants, limes are evergreen. This is not a cold hardy plant as the peel is very thin. Even if you've had some success with other citrus, you may find the lime to be a challenge. Julian Sauls, Professor at Texas A&M, notes that there are very few lime tree problems that the backyard gardener will face. Insects and simple diseases may cause some blemishes to the peel, but the flesh will probably remain unaffected. Popular varieties include Bearss Seedless, Key, Persian, and Tahiti.
The kumquat is the strangest of the citrus plants. While lemons, limes and oranges may be part of the same family, the kumquat is more of a second cousin. The fruit looks like an orange in color and texture, but the shape is small and oval. The biggest challenge with a kumquat is not so much growing it, but eating it. Unlike an orange, the flesh is very sour, but the thin skin is very sweet. To eat, roll the kumquat in your hand to release the oils, then take a bite. Do not peel; eat it skin and all. Take time to chew the edible skin and allow the sweetness to emerge from the skin. If you swallow too quickly, expect your mouth to pucker from the extreme sourness. The fruit has small seeds that can be swallowed or spit out. Cold hardy, the kumquat can survive in temperatures as low as 10 degrees. Popular varieties include Miewa and Nagami.