How to Grow: Citrus

There’s nothing like the taste of home grown citrus. Unfortunately, only gardeners in USDA hardiness zones 8 and warmer usually get this experience. But even gardeners in colder climates can enjoy some citrus in containers grown as houseplants in winter and moved outdoors in summer. In warm climates citrus can grow into medium-sized trees (20 to 30 feet). But grown in a container they stay manageable and dwarf.

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Outdoors grow citrus trees in the yard as a specimen plant or grow dwarf varieties in a mixed shrub border or as a foundation plant. In containers grow citrus on sunny decks, patios and against south-facing walls and buildings in summer to maximize the amount of heat they receive.

Attractive Varieties

‘Improved Meyer’ lemon, ‘Bearss’ lime, ‘Calamondin’ orange and kumquats are good container types. These trees tend to stay 6 to 12 feet tall. Outdoors there are many choices depending if you are in the humid Southeast or dry West. ‘Moro’ blood oranges, ‘Satsuma’ mandarin orange, ‘Fremont’ tangerines’, and ‘Oroblanco’ grapefruits grow well out West. ‘Valencia’ navel orange, ‘Redblush’ grapefruit, and ‘Dancy’ mandarin orange are some choices for the Southeast.

Good Companions

Outdoors plant full sized trees near other acid-soil loving shrubs such as camellia. Plant dwarf varieties as structural plants with other flowers nearby such as lavender and lamb’s ear. Don’t plant directly under citrus since they have a shallow root system and don’t compete well with other plants. Place containers in the garden, protected from cold winds, on sunny decks and patios.

Planting

Plant trees outdoors in a full to part sun location on well-drained, fertile soil. Space trees 10 to 15 feet apart, depending on the selection. In marginal hardy areas, place the trees in microclimates where they will be protected from frost. Plant citrus in containers filled with a mix of potting soil and compost in spring.

Growing

Keep citrus trees fertilized monthly during the growing season with special plant food formulated for citrus. Citrus prefer infrequent deep waterings, versus frequent shallow watering. Use a time-release fertilizer applied in spring for container citrus trees. Many citrus trees are grafted onto rootstocks. Prune off any shoots arising from below the graft union. Also, prune dead, diseased, broken branches and to balance and shape the plant.

Plant disease resistant varieties for your area. Control aphids, scale, and mealybug pests by spraying insecticidal soap on aphids, horticultural oil on scale and dabbing mealybugs with cotton swabs dipped in rubbing alcohol.

Move container citrus indoors once the air temperatures dip below 40F. Place the trees in a sunny window and keep the soil barely moist, but keep the humidity high by grouping plants together or using a humidifier. Some citrus, such as lemons and limes, will continue to flower and fruit indoors.

Harvesting

Different citrus mature at different times of the year depending on the selection. Harvest citrus when they have matured to the final color. Try a few fruits to gauge their sweetness. Citrus will not continue to ripen once picked.

Excerpted from the book, Foodscaping, (CSP, 2015)

Go here for a video on how to plant a tree