Evergreen, Edible fruit, Shrubs, Trees, Decorative fruit or berries
As landscaping plants, citrus offer year-round attractive form and glossy deep green foliage; also bear fragrant flowers and decorative fruit in season. If you want quality fruit, your choice of varieties will depend on the total amount of heat available through the fruit-developing period (need varies according to type) and on the winter cold in your zone.
Citrus flowers attract bees.
For detailed information about citrus selection and growing, see How to choose and grow citrus.
Originally hybrids between oranges and pummelos, grapefruit trees can reach 25–30 ft. tall (most are shorter), with large, dark green leaves. True grapefruit needs heat for sweet-tart fruit; it's best in Florida, south Texas, and the desert, where fruit ripens in 9 months (can take a year or longer where there’s less heat). Vigorous grower. Intermediate in cold resistance.
Low heat requirement makes lemons widely adapted and especially appreciated in regions where sweet oranges and grapefruit won’t ripen. Theyse do best year-round near the coast, though some varieties are very successful in the desert.Citrus (Lime)
The various limes range from moderately to extremely cold sensitive; they are most reliable in areas where hard frosts are uncommon. Can succeed in colder areas if grown in pots and protected in winter. Depending on variety, fruit may be intensely sour or nearly devoid of acid.
The commercial oranges are typified by 'Washington' navel and 'Valencia'.
Arizona Sweets is a group of varieties grown in Arizona. Many are also grown in Florida. They include 'Diller', which bears small to medium-size oranges with few seeds and high-quality juice in late fall (before heavy frost) on a vigorous, large, dense tree with large leaves; 'Hamlin', similar but not as hardy, producing medium-size fruit; 'Marrs', with tasty, low-acid, early-ripening fruit on a naturally semi-dwarf tree that bears young; and 'Pineapple', tending to bear rich-flavored, seedy fruit in alternate years.
Blood oranges are characterized by red pigmentation in flesh, juice, and (to a lesser degree) rind. Flavor is excellent, with raspberry overtones. Generally, they thrive wherever sweet oranges produce good fruit. Pigmentation varies with local microclimates and weather. 'Moro' bears fruit with deep red flesh and variable amounts of red on the rind from early winter to early spring (no rind pigmentation on the coast); 'Sanguinelli' has red-skinned fruit and flesh streaked with red from late winter to mid-spring; and 'Tarocco' produces fruit with red or red-suffused pulp and pink to red juice from early to midwinter (color varies from year to year), with good quality in cooler areas. 'Tarocco' is very vigorous and open growing, with long, willowy, vine-like branches; dwarf makes ideal espalier.Citrus (Pummelo)
A vigorous grower, reaching 15 to 30 ft. tall, with 4 to 8 in. leaves. This forerunner of the grapefruit bears clusters of enormous round to pear-shaped fruits with thick rind and pith. Once peeled, fruit is just slightly bigger than a grapefruit. Different varieties range in flavor from sweet to fairly acidic. Needs a little less heat than grapefruit. Ripening starts in winter in warmest areas. To eat, peel the fruit, separate the segments, and remove the membrane surrounding them. Because pullelo fruit is so heavy, prune pummelo trees to encourage strong branching.How to choose and grow citrus
Heat requirements. Generally, sweet-fruited varieties need moderate to high heat to form sugars, sour types less heat. Lemons and limes require the least warmth and will produce usable fruit in cool-summer areas (as long as winter temperatures are not too low). Valencia orange has a lower heat requirement and greater frost tolerance; it is adapted to Florida and areas near Southern California coast. Navel oranges demand even more warmth and are better suited to inland regions; their fruit development period is shorter than that of Valencia, so trees will produce palatable fruit between winter frosts if summer heat is high. Mandarins (tangerines) require high heat for top flavor and are best adapted to inland areas. Grapefruit develops full flavor only where trees receive prolonged high heat, as in the low desert. (In cooler areas, you re better off growing grapefruit-pummelo hybrids Oroblanco and Melogold, which produce sweet fruit in more moderate temperatures.)
Hardiness. Citrus plants of one type or another are grown outdoors all year round in regions with warm to hot summers and mild winters. Lemons, limes, and citrons are most sensitive to freezes. Sweet oranges, Improved Meyer lemon, grapefruit, and most mandarins and their hybrids are intermediate in cold resistance. Kumquats, satsuma mandarins, sour oranges, and calamondin are the most cold resistant, with kumquats the hardiest of all, withstanding temperatures in the high teens.
Other factors affecting a tree's cold tolerance include preconditioning to cold (it has greater endurance if exposed to cold slowly and if first freeze comes late), type of rootstock, and location in garden. Prolonged exposure to freezing weather is more damaging than a brief plunge in temperature. All citrus fruit is damaged at several degrees below freezing, hence the importance of choosing early-ripening varieties in freeze-prone areas.
Growing citrus in Hawaii. Home gardeners in Hawaii can grow many of the varieties grown on the mainland, plus some specialty types adapted only to the islands. However, citrus grows differently in Hawaii, and the fruit often looks and tastes quite a bit different from the same variety grown in California, Arizona, or along the Gulf Coast. The trees tend to bloom almost year-round, so harvest is nearly continual. The lack of cool nights results in a rind that s thinner and more greenish than the thicker, brightly colored skin of fruit grown in California. Lack of cool nights also reduces acid content, which is why Hawaiian citrus tastes sweeter. The fruit is very juicy as well.
Standard or dwarf. Practically all citrus plants sold have been budded or grafted on an understock. Grafted trees begin bearing fruit in just a few years, contrasted to 10 to 15 years for seedling trees. Standard trees (20—30 ft. tall and as wide) are grown on a variety of understocks. Dwarf trees are grown on understocks of trifoliate orange (Poncirus trifoliata) or Flying Dragon; the latter is a naturally dwarf, contorted, spiny form of trifoliate orange. Ordinary trifoliate orange understocks produce trees 8—10 ft. tall (some may reach 15—20 ft.). Flying Dragon produces even smaller trees (5—7 ft. at 13 years). Check citrus trees periodically for suckers (branches that arise below the graft line) and remove them before they compete with (or overwhelm) the desired variety. Some tender citrus, such as limes, are grown from cuttings; if such trees are killed to the ground by severe cold, they will resprout from the roots and remain true to type.
Harvest periods. Most citrus varieties ripen their fruit from late fall into winter, but some varieties, such as Valencia orange, ripen into spring and summer. In addition, many types can hold their fruit on the tree for long periods without loss of quality. By growing both Washington navel and Valencia oranges, for example, you can have fresh fruit almost 10 months of the year. Everbearing citrus like lemons and limes can produce throughout the year, but they fruit most heavily in winter and spring.
Citrus fruit ripens only on the tree. The best way to judge its ripeness is to pick a fruit and taste it; rind color is a poor indicator, since many varieties are fully colored before they are edible.
Drainage. Fast drainage is essential. If soil drains slowly, don't try to plant citrus in it regardless of how you condition it. Instead, plant above soil level in raised beds or in a mound. Drainage in average soil (and water retention in sandy soil) will be improved by digging in a 4—6-in. layer of organic matter (such as garden compost or ground bark) to a depth of about 1 ft.
Watering. Citrus trees need moist soil, but never standing water. They also need air in the soil. Danger from overwatering is greatest in clay soil where air spaces are minute. In soil with proper drainage, water newly planted trees almost as frequently as trees in containers twice a week in normal summer weather, more frequently during hot spells. Water established trees every other week during summer. In clay soils, space watering intervals so top 4—6 in. of soil dries between irrigations. Don't let tree reach wilting point. Be sure to water consistently. Fluctuating soil moisture can aggravate fruit splitting, a problem that can affect all citrus, but especially navel oranges (typically in autumn). If you build basins, make them wider than spread of branches. Citrus roots extend out twice as far as the distance from the trunk to branch ends. Keep trunk dry by starting basin 6 in. or more from trunk. When you water, be sure to wet the entire root zone (that is, soak the soil to a depth of 3—4 ft.).
Mulching. Since citrus roots grow near the surface as well as deeper, a mulch over the soil is beneficial. Use a 2—3-in. layer of compost or other organic matter to help maintain soil moisture. In mild-summer areas, large pebbles or gravel will increase reflected heat and hasten ripening. Don't allow grass to grow near the trunks of citrus trees. Instead, maintain a grass-free, mulched area under the canopy.
Fertilizing. Nitrogen is the main nutrient that must be supplied in all regions. If you garden in sandy soil, choose a complete fertilizer containing a full range of nutrients. Apply 2 oz. actual nitrogen the first year after a newly planted tree puts on new growth; then increase the amount by 4 oz. each year for the next few years. After the fifth year, apply 1—1 1/2 lb. yearly. (Depending on tree size, give plants growing in raised beds or with restricted root space as well as trees grafted onto 'Flying Dragon' rootstock about a third to half the recommended amount after the fifth year.) To determine weight of actual nitrogen, multiply percentage of total nitrogen (as stated on fertilizer label) by total weight of fertilizer.
Divide total fertilizer into several feedings throughout the growing season. In freeze-prone areas, start feeding in late winter and stop in late summer. Make sure trees are well watered before feeding. Spread the fertilizer beneath and a foot or two outside the branch spread of the tree; then water it in deeply.
Citrus trees that receive too much or too little nitrogen show the evidence in leaf color. Dark green, lush leaves with burned tips or edges indicate too much nitrogen; yellowish leaves are a sign of nitrogen deficiency.
Citrus may suffer from chlorosis due to iron, manganese, or zinc deficiency. In iron chlorosis, leaves turn yellow from edges inward; veins remain dark green. (Same symptom may be caused by overwatering, so check your irrigation practices.) Manganese deficiency shows up as fine mottling, usually on young leaves, and as pale or yellowish areas between dark green veins. Signs of zinc deficiency are yellowish blotching or mottling between leaf veins. Manganese and zinc deficiencies may occur together and be difficult to distinguish from each other. Commercial products containing chelates of all three nutrients are available as foliar sprays.
Pests and diseases. Citrus can get aphids, mites, scale insects, and mealybugs. If these pests natural enemies fail to handle the infestations, and if jets of water fail to keep the pests in check, spray with appropriate chemicals. If scale remains troublesome, spray with horticultural oil in early spring. Control snails and slugs whenever necessary, especially during warm-night spells in winter and spring.
Copper bands, available in some areas, will keep snails out of trees. Where it is legal to do so (in Southern California), colonize citrus groves with decollate snails, which prey on the garden snail.
The citrus bud mite causes weirdly deformed fruit (especially lemons). Control with horticultural oil spray in spring and in fall; spray only in fall in hot-summer areas. Reduce harmful insect populations by keeping ants out of trees with sticky bands on trunks. (Ants prey on natural insect predators of the mites.)
The few fungal ailments of citrus occur in poorly drained soil. Water molds, causing root rot, show up in yellowing and dropping foliage. Best control is to correct your watering schedule.
Brown rot gummosis usually occurs in older trees at base of trunk. Keep base of trunk dry; trim and clean the oozing wounds, removing decayed bark to a point where discolored wood does not show. Paint areas with Bordeaux paste mixture.
Sunburn. The bark of newly planted citrus trees is subject to sunburn in hot-sun areas. Trunks should be wrapped (paper trunk bands are available commercially). When heavy pruning exposes trunks or limbs, protect bark with whitewash or latex paint diluted by half with water.
Pruning. Commercial trees are allowed to carry branches right to ground. Production is heaviest on lower branches. Growers prune only to remove twiggy growth and weak branches or, in young plants, to nip back wild growth and balance the plant. You can prune garden trees to shape as desired; espaliering is traditional, though espaliered citrus is not very productive. Lemons and sour oranges are often planted close and pruned as hedges. Lisbon and Eureka lemons should be pruned to keep the trees within bounds and the fruit easily reachable. Many citrus are thorny, so wear gloves and a long-sleeved shirt when picking fruit or pruning. In freeze-prone areas, don t prune in fall or winter. Wait until late spring or summer to prune frost-damaged trees new growth will make it clear which wood is dead. If you re growing a multiple-variety citrus tree, you must continually cut back the vigorous growers (lemon, lime, pummelo, grapefruit) so the weaker ones (sweet orange, mandarin) can survive. On all citrus, remove fruit from newly planted trees so that the trees energy will be channeled into new growth rather than fruiting.
Citrus in containers. In general, containers should have a diameter of at least 1 1/2 ft., though calamondin and Chinotto sour orange can stay in 8—10-in. pots for years. Plant in light, well-drained soil mix. Daily watering may be necessary in hot weather. Fertilize monthly from midwinter to mid-autumn with high-nitrogen liquid fertilizer containing chelated zinc, iron, and manganese.
Potted citrus can stay outdoors all year in mild-winter climates, but plants should be moved to a protected location if a freeze is predicted. In cold-winter regions, shelter plants in winter; a cool greenhouse is best, but a basement area or garage with good bright light is satisfactory. Most container-grown citrus will need to be root-pruned and repotted in fresh soil every 4 or 5 years to remain healthy.
Citrus as houseplants. There s no guarantee of flowering or fruiting indoors, though plants are still appealing. Improved Meyer and Ponderosa lemons, Bearss lime, kumquats, calamondin, and Rangpur sour-acid mandarin are most likely to produce good fruit. Locate no farther than 6 ft. from a sunny window, away from radiators or other heat sources. Ideal humidity level is 50 percent. Increase moisture by misting tree; also ring tree with pebble-filled trays of water. Water sparingly in winter.
This is an early, almost seedless version of 'Valencia', which is the juice orange of stores. Widely adapted from Florida to Texas and in California, but a poor risk in Arizona.‘Campbell Valencia’ oranges mature in early summer and store on the tree for months, improving in sweetness. This is a vigorous tree, fuller growing than ‘Washington’, both as standard and dwarf. Expect it to reach 25—30 ft. high and wide.'Clemantine'
Fruit a little larger than ‘Dancy’, with fewer seeds. Ripens late fall into winter; remains on tree for months, staying juicy and sweet. Seems to develop full flavor in areas that are too cool for a good ‘Dancy’. Tree reaches 12 ft., semiopen with vertical, spreading, somewhat willowy branches. Usually bears light crops without another variety for pollination.
Grows 12 ft. high and wide. This is the standard tangerine that appears in markets before Christmas. Smaller and seedier than other mandarins, it develops its best flavor in Florida and in Southwest Zones 12 and 13, but it's also good in Zones 21–23. Ripens late fall into winter; holds well on tree. Upright tree with erect branches. Dwarf tree handsome in container or as espalier. This is an alternate bearer.
The word “improved“ refers to fact that this is a disease-free form of 'Meyer' lemon (which is itself probably a cross between lemon and sweet orange), and the only one that can be sold in California. This is the best lemon for Hawaii. Fruit is quite different from commercial lemon“rounder, thinner skinned, orange yellow in color. Tangy aroma but less acidic flavor than standard lemon; very juicy. Bears fruit year-round and starts producing at an early age. Tree is not a dwarf on its own roots, though it is sometimes sold as an own-root plant that can reach 12 ft. tall, 15 ft.wide. On a dwarf rootstock, it“s half that size.
Kumquats are shrubby plants 6–15 ft. high or taller, with yellow to red-orange fruits that look like tiny oranges. Eat whole and unpeeled–spongy rind is sweet, pulp is tangy. Best in areas with warm to hot summers and chilly nights during fall or winter ripening period. Hardy to at least 18–F/–8–C.
Nagami is the main commercial variety. Oval, slightly seedy fruit is more abundant and sweeter in hot-summer climates. Plant is thornless.'Owari'
This is thee main satsuma grown in the West. Spreading, often drooping branches with large leaves. Grows to a rounded 15–20 ft., half that size as dwarf.'Variegata'
Fruit looks like tiny (3/4—1 1/2-in.) orange. Hundreds hang from this tall, columnar plant (8–10 ft. tall and about half as wide, even as dwarf ). This varaiety is variegated, its leaves marked with creamy yellow; developing fruit may be striped in yellow and green. Flesh is tender, juicy, sour, with a few small seeds. Skin and flesh are good in marmalades.'Washington'
Can have fresh fruit almost 10 months of the year. Widely adapted except in desert regions; best in warm interiors. Standard tree is 20–25-ft. globe. On dwarf stock, it grows 8–12 ft. high.
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