HOME FRUIT PRODUCTION-MISCELLANEOUS CITRUS
Julian W. Sauls, Ph. D.
Professor & Extension Horticulturist
Texas Cooperative Extension
There are a number of citrus fruits which do not fit into the usual categories, so they are described here. Some are edible, some are strictly ornamental and some are grown for both purposes. These citrus fruits can be readily grown in the Valley and some have sufficient cold hardiness to be grown throughout south and southeast Texas. All require full sun for optimal growth and all require deep, well-drained soils. All will ultimately require some means of cold protection to avoid damage. Generally, these citrus should be planted and grown just like other citrus in terms of cultural practices and pest control.
Pummelo, which produces the largest fruit of all citrus, is also known as shaddock after the name of a ship's captain who is believed to have introduced its seeds to the West Indies near the start of the eighteenth century. Its similarity to grapefruit leaves little doubt that pummelo was the progenitor of grapefruit. Pummelos are characterized by very large, thick-skinned fruits having coarse flesh with a distinctively musky aroma and flavor. Both pink fleshed and white fleshed types exist, varying from mildly sweet to very acid.
Unlike other citrus, the juice sacs do not rupture easily and they readily separate from the segment membrane. The juice sacs can thus be consumed separately, with or without sugar, or as a salad base.
'Chandler' is a pink-fleshed variety developed by the University of California. It is sweet, with seediness depending upon proximity to pollinizers. 'Reinking' is a white-fleshed, seedy pummelo developed by the U.S.D.A. Both mature in November, with fruit holding well until February. Numerous other varieties exist, especially in the Orient where pummelos are quite popular.
Pummelo is a little less cold hardy than grapefruit. While marcot (air layer) is a common means of propagation in Asian countries, trees in Texas are commonly budded onto sour orange seedling rootstocks. Cultural practices are the same as for grapefruit.
Kumquats are native to China and are the most cold hardy of all edible citrus. The tree is usually small and shrubby, mostly thornless and adapts well to container culture. Fruit are small and showy, bright yellow to orange in color, few-seeded and not very juicy. The peel is fleshy, thick, aromatic, spicy and edible. The fruit matures in late November and can be eaten whole; it is also candied and used for marmalade.
Kumquat trees become semidormant from fall into spring, with growth occurring only at relatively warm temperatures. Consequently, kumquats bloom much later than other citrus.
Fruit of 'Nagami' is oval to oblong and acid, although its rind is sweet. Fruit of 'Meiwa' is round, with sweet rind and flesh. Fruit of 'Marumi' is round, but smaller than that of 'Meiwa', and acid.
Kumquats have been hybridized with limes to produce limequats and citranges to produce citrangequats--the former being described in Home Fruit Production-Limes, the later being described later in this manuscript.
While kumquats can be grown from seed, seedlings are considered weak and inferior. Both marcots and rooting cuttings can be used, but kumquats are often budded onto 'Cleopatra' mandarin, calamondin or trifoliate orange seedlings. Cultural requirements are the same as for other citrus.
Citron probably originated in northeastern India and is undoubtedly the first citrus fruit known in Europe inasmuch as it has been cultivated in the Mediterranean basin for over three millennia. The fruit is large, usually oblong with a pronounced nipple, with yellow, very thick, fleshy peel. The fruit is essentially inedible, as there is little flesh or juice. The peel is brined and candied for use in fruit cakes and other confections. The peel oils are intensely aromatic and pleasantly so--the odor of a single fruit can permeate an entire house for days. The fruit has long been an important part of some religious functions.
The tree is straggly, thorny and small. Citron is the most cold sensitive of all citrus, more so even than lemons and limes. 'Etrog' and 'Diamante' are acid forms, 'Corsican' is sweet. 'Buddha's hand' is unique among fruits in that the fruit is split from the blossom end into numerous, finger-like projections.
Cultural requirements of citrons are the same as for lemons or limes. Propagation is by seed, cuttings and budding.
Calamondin is primarily grown as a house plant and is often called 'miniature orange". It originated in China and its fruit closely resemble mandarins, although they are fairly small and quite acid, with few seeds. The juice is sometimes used as a lemon or lime substitute. The plant is bushy, normally dwarfed and nearly thornless.
Calamondin bears year round, which increases its appeal as an ornamental. The tree is more cold hardy than oranges. A variegated form exists, having green and white to yellow leaves.
Propagation is from seed and cuttings rooted under mist. It is commonly used as a rootstock for kumquats, but its greatest use is for ornament. Cultural requirements are the same as for other citrus.
Citrangequats are trigeneric hybrids involving kumquat and citrange, the latter of which is a hybrid of trifoliate and sweet orange. One objective of the breeding program of U.S.D.A. in the early twentieth century was to combine the cold hardiness of kumquat and trifoliate orange with the quality of sweet orange. Only three citrangequats were ever named; they do have good cold hardiness, though eating quality is very poor to nonexistent.
'Sinton' is the result of a 'Nagami' kumquat X 'Rusk' citrange cross that has small, obovate fruit of good reddish color, acid flavor and few seeds. The tree is upright, nearly thornless, with mainly unifoliolate leaves. It was named in 1923 for Sinton, TX, where it first fruited. As an ornamental, it is hardy and attractive.
'Telfair' resulted from a cross between 'Nagami' kumquat and 'Willits' citrange and was named for Telfair County, GA. Its fruit and tree are similar to 'Sinton' except that it is thorny and has mainly trifoliolate leaves.
'Thomasville' is a sibling of 'Telfair' that first fruited in Thomasville, GA. Its fruit are a little larger than the other two citrangequats; it is somewhat seedy. The tree is similar to 'Telfair'. 'Thomasville' is considered edible at full maturity, but "edibility" is relative, as few people can be convinced to taste it a second time.
All in all, the citrangequats are very ornamental and cold hardy and should succeed wherever kumquat or trifoliate orange can be grown. Propagation is primarily by budding. Cultural requirements are the same as for other citrus.
Trifoliate orange is the most cold hardy of all citrus. It is deciduous, unlike other citrus, and very thorny. The author saw mature trifoliate hedges growing in Fort Worth, TX, in the early 1970's. Its fruit are completely inedible, containing an acrid oil that is very unpleasant to the taste. It matures in late summer.
There are small-flowered and large-flowered types, with the former said to impart greater cold resistance while the latter is believed to be more dwarfing. There are literally dozens of trifoliates but only a few have been named in the United States. 'Rubidoux' is a California selection of the small-flowered group that has been used in California. 'Flying Dragon' is a dwarfed ornamental type from Japan that has large, downward curving spines (thorns) and very small, linear leaves. Both are widely used as rootstocks for mandarins in Southeast Texas, as are other, local, selections from seemingly feral trifoliate trees.
Propagation is from seed. Cultural requirements are about the same as for other citrus.
The sour oranges were among the first citrus to be introduced to the Americas, where they became feral in areas of warm, humid tropical and subtropical climates. The sour oranges are principally used for marmalade, with specialty use in liqueurs and perfumes. In Texas, sour orange is the rootstock on which more than 99 percent of the industry is planted.
The tree is vigorous, usually armed with long spines (thorns) and hardier than sweet orange. The fruit is large, commonly rough skinned and yellow, with white, very acid flesh and juice. The fruit are very seedy.
'Chinotto' is a myrtle-leaf orange closely related to the sour oranges that makes a very attractive ornamental. The tree is densely foliated, compact and nearly thornless with the same cold hardiness as sour orange. The fruit resembles a small orange with yellowish peel. It is acidic in flavor and seedy; the fruit stores very well on-tree and is used in preserves.
Sour oranges are primarily grown from seed, though 'Chinotto' may be budded onto sour orange seedlings. Culture is the same as that for other citrus.
Home | Texas Citrus Industry | Citriculture | Pest Management | Harvest and Handling | Marketing
Orchard Economics | Resources | Urban Citrus and Subtropical Fruits
This page revised July 26, 2005