Choosing Citrus Varieties for Hot-Zone Climates
Hardiness, taste, and ripening timeframe are important factors
Thinking about planting a citrus tree? Most types of citrus are relatively easy to grow and care for. If you choose the right type for your climate, growing citrus is a good choice for advanced and beginner growers alike. The best time of year to plant citrus is in the spring after all danger of frost has passed.
It's worth giving thought to which type of citrus you are going to plant before you begin digging the hole. Amazingly, one of the three original Washinton Navel orange trees brought to the United States and planted in 1873 is still producing fruit. Your tree may not last that long, but it is worth making an informed decision before you plant.
Two factors to consider when deciding which type of citrus tree to plant are:
- Which type of citrus grows best in your hardiness zone
- What time of year is the fruit ready to harvest.
Determining the Best Citrus for Your Region
Travita oranges (top photo) and Ruby Red grapefruit ripening on the tree.
Citrus trees have varying levels of frost tolerance, so it's important to choose the type of citrus tree best suited to your climate. All citrus trees are frost-tender and are likely to be damaged by freezing temperatures. Because of this, citrus trees are usually grown in hardiness zones 9-11. Some colder zones can push the boundaries of growing citrus by planting the most frost-tolerant varieties and/or growing citrus in containers that can be moved to a sheltered location during the coldest times of the year.
Even within zones 9-11, it is important to remember that each locale and even parts of your yard may have areas where it is too cold to grow citrus well.
If cold weather is a concern, remember that cold air flows to low areas in the landscape such as the base of mountains or a hill. Low areas in the landscape have cooler temperatures than surrounding areas. Choose a sunny location on the south or east side of the yard with shelter from the northern wind. In addition, planting a tree next to a wall that receives sun in the winter may protect the tree in cold weather.
That being said, it is a good idea to protect citrus trees during freezing temperatures no matter where they are planted in your yard. If freezing temperatures are expected, water all citrus trees deeply no matter their age. Moist soil helps retain the heat in the soil. During frost events, cover citrus trees with frost cloth or burlap, being careful to completely drape the tree from the top all the way to the ground to trap radiating heat from the ground. If extra frost protection is desired for young trees, wrap trunks with cloth or burlap until the danger of frost is past in the spring.
Citrus Frost Tolerance: General Guidelines
|Type of citrus||Frost tolerance of mature dormant* tree||Notes|
|Lime||32 degrees F.||
|Lemon||High 20s degrees F.||
|Sweet, navel and valencia oranges||Mid 20s degrees F.|
|Grapefruit||Mid 20s degrees F.|
|Mandarin||Low 20s degrees F.||
|Calamondin||20 degrees F.|
|Kumquat||18-20 degrees F.|
*As temperatures fall, many citrus trees go into a type of dormancy — not true dormancy but a dramatic slow-down of growth. As temperatures climb heading into spring, trees come out of this semi-dormant state and produce new growth and blossoms. Young trees are more sensitive to cold than mature trees; they have a shallower root system and are more susceptible to frost damage.
Harvest Times for Various Citrus
Ripe clementine (top photo) and ripe lemons.
Knowing when citrus is ready to harvest also influences the decision of which type of citrus tree to plant, especially if you have more than one variety of citrus tree. Staggering harvest times helps ensure less waste of the tasty home-grown fruit. Choose varieties of the same type of citrus that ripen at different times to extend your harvest season.
Some types of citrus have a harvesting window as little as 2 months, while others remain ripe on the tree for several months. Harvest fruit anytime during the harvesting window for each type of citrus.
Rind color does not always indicate ripeness. The color of citrus is affected by the weather, not necessarily the ripeness of the fruit. The best way to tell if citrus is ready to eat is to try one or two at a time until the taste suits you. The longer citrus fruit remains on the tree, the sweeter it becomes. As the fruit ripens, the acid content goes down and the sugar content goes up. Once picked, the fruit will not ripen anymore. Once unpicked fruit is past its prime, it may become soft, harden on the vine, or drop.
Exact months for ripening varies depending on your location. (Arizona dates differ slightly from California and Florida, etc.) But they follow a similar pattern with lemons and limes ripening first.
Approximate Citrus Harvesting Dates
(Months listed are for the low desert of Arizona)
|Type of citrus||Ripe during the following months||Notes|
|Limes||August-January||Mexican key limes often produce all year.|
|Kumquats||October-March||Often sets bloom and ripens all year.|
|Sweet oranges||December-February||Hamlin and Marrs ripen first.|
|Valencia oranges||February-May||Best orange for juicing.|
Dry vs. Humid Climates
Citrus fruit varieties grown in hot, dry regions are similar to those grow in humid climates. The difference is which type of rootstock the citrus is grafted onto — for example, certain rootstocks may be better adapted to certain soils. Some citrus-producing states regulate the importation of citrus trees; if you live in one of these states you may need to purchase your tree from a source located within your state.
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