A healthy backyard citrus tree needs five things: pruning in late winter or early spring, a balanced citrus fertilizer three times a year, regular checks for pests, deep and infrequent watering, and at least 8 hours of direct sun with protection on frosty nights. These tips come from JP Beall, a Redlands citrus grower.
There are few things better than fruit off your own tree. To me the best months of the year run from January to March, when the Navel oranges, tangerines and tangelos ripen around my house. Then comes the smell of the blossoms, which had Old Californians sleeping on dedicated sleeping porches just to breathe the perfumed air.
When I'm at shows for Old California Botanicals, people often ask for advice. Some are planting their first tree; others bought a house with trees that aren't producing. Here are five simple tips from me, a citrus grower and board member of the county Farm Bureau.
When and how should you prune a citrus tree?
Prune in late winter or early spring, before the growing season begins. The exception is a winter-fruiting or winter-blooming variety: don't prune while the tree is fruiting or flowering. Pruned correctly, a fruit tree puts more of its energy into the fruit and into the places you want fruit to grow.
If you hire a professional, make sure they're trained in fruit trees or have pruned for a commercial grower (some also serve home gardens). Ask around at a local fruit tree nursery. If you'd rather learn yourself, start with these principles:
- Where two branches cross, cut the smaller one at its base, so they don't rub and open wounds for insects and disease.
- Control vertical growth early so the tree stays easy to pick. You can't really prune an already tall tree down to size, so be consistent.
- Thin branches to improve airflow, which reduces the chance of pests and pathogens.
- Cut branches that trail to the ground ("skirting" the tree), so the tree doesn't set low fruit that pests will find.
- Clean your loppers and clippers before you start, between each tree and when you finish. Keep a bucket of 10% bleach solution to rinse tools in, or keep a container of Clorox Disinfecting Wipes with your pruning gear.
What fertilizer does a citrus tree need?
Citrus trees have specific nutrient needs, and a balanced fertilizer matters for growth and fruit. Use a citrus fertilizer with a balanced ratio of nitrogen, phosphorus and potassium, such as a 16-16-16 fertilizer (this one comes in several bag sizes if you don't want to carry 50-pound bags). Apply it in late winter, early spring and late summer for a steady supply. Don't over-fertilize: too much leads to leafy growth at the expense of fruit.
How do you keep pests off a citrus tree?
Citrus trees are prone to aphids, scale insects and citrus leaf miners. Besides regular pruning:
- Inspect the leaves, stems and fruit regularly for signs of infestation.
- Consider beneficial insects such as live ladybugs, or parasitic wasps. Some studies suggest California brittlebush, a Southern California native, attracts predators of the Asian citrus psyllid (here's a source for brittlebush seeds).
- Treat every 2 to 3 months. Neem oil is an organic option for common citrus pests and also works as a fungicide on fruit trees, vegetables and roses. I buy neem oil concentrate so I can control the strength. On the fruit trees in my garden I also use BioAdvanced Citrus Tree and Vegetable root drench every 2 to 3 months; it's a systemic treatment taken up through the roots when you water. Follow the label.
These steps matter most against the Asian citrus psyllid and the Oriental fruit fly, one of the newest invasive pests worrying citrus farmers and home gardeners. When this post first ran in 2024, quarantines for both farmers and gardeners were in place in Santa Clara, San Bernardino and Riverside counties (details here).
Early detection stops damage to your tree and your fruit, and stops pests spreading to your neighbors. Report sightings to your county agricultural department. The CDFA's pest page shows how to identify the major pests if you grow citrus in California. Pests sometimes arrive on the bottoms of cardboard boxes, so check your packages.
How often should you water a citrus tree?
Water deeply and let the soil dry out between waterings. In a hot, dry climate it's tempting to water often, or the tree may sit near sprinklers and get frequent light waterings, but the opposite is recommended. I find one long, deep soak a month, especially in dry spells, works well for my trees.
Make sure the soil drains well to prevent root rot, or adjust your watering if you have clay soil. Some of the best Washington Navel oranges are grown in clay, though that's a matter of heated debate among farmers. If the leaves turn yellow, the tree may be getting too much water; cut back. Adjust the schedule to your climate and your variety.
How much sun does a citrus tree need, and how do you protect it from frost?
Citrus trees need full sun, so choose a spot with at least 8 hours of direct sunlight a day. Varieties differ in cold tolerance, and your elevation and microclimate may decide what grows well in your yard. In mine, lemons and limes haven't done well, but friends down the hill have bumper crops.
Watch the freeze risk. If citrus fruit sits at 28°F for 6 hours or longer over three consecutive days, you'll lose the fruit, and frozen citrus is not a pretty sight. When temperatures have dropped into the teens, water has frozen inside citrus trees and split the trunks, killing the tree. That's why commercial groves have used smudge pots and wind machines. On frosty nights:
- Cover the tree and other cold-sensitive plants with frost cloths or old bedsheets.
- Water the tree before a freeze. Moist soil holds the temperature just above freezing for longer.
- If your citrus is in a container (dwarf varieties do well as topiaries, in greenhouses or in sunny rooms), move it somewhere sheltered.
Good pruning, feeding and pest care add up. Put these into your routine and you'll be picking your own citrus in no time. When your tree is between crops, our California citrus marmalades and Navel Orange Essential Oil keep the grove close.
Frequently asked questions
When is the best time to prune a citrus tree?
Prune in late winter or early spring, before the growing season. Don't prune a tree while it is fruiting or flowering.
How often should you fertilize citrus trees?
Apply a balanced citrus fertilizer, such as 16-16-16, three times a year: late winter, early spring and late summer.
Why are my citrus tree's leaves turning yellow?
Yellow leaves can be a sign of overwatering, especially on trees near sprinklers. Water deeply and let the soil dry out between waterings.
What temperature damages citrus fruit?
Citrus fruit is lost if it sits at 28°F for 6 hours or longer over three consecutive days. Cover trees and water the soil before a freeze.
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