The Rangpur lime is believed to have resulted from a cross between the lemon (Citrus limon) and the mandarin or tangerine (C. reticulata). It is more cold hardy than the lemon or lime and every bit as sour as either. The tree is fast growing to 15 or 20 ft (4.5 or 6 m) tall, with spreading and somewhat drooping branches. Thorns are small and few. The very pretty flowers are tinged with purple and as fragrant as any orange blossom. The fruits are deep reddish orange and look like mandarins (a.k.a. satsumas, tangerines), but they taste like limes. Fruits peel easily to reveal 8-10 easily separated bright orange segments with a few greenish seeds. They are quite juicy. Rangpur lime bears abundantly from November through winter, and the fruits persist on the tree in good condition.
Location Citrus X limonia probably originated as a hybrid between C. limon and C. reticulata in India. It was introduced into the U.S. through Florida in the late 1800's. Rangpur lime is often grown as an ornamental in Florida and occasionally as a minor commercial fruit tree in Australia, Tahiti and California.
Before - Rangpur limes are as easily peeled and sectioned as a tangerine.
After - Ruthie Belle's Famous citrus pie - Rangpur lime variant.
Culture Light: Any citrus variety will survive in partial shade, but all produce more fruit in full sun. Moisture: Established trees need only average watering. Hardiness: USDA Zones 8-11. Rangpur lime tolerates frosts and light freezes, and has survived temperatures of 22 F (-5 C) unscathed here in North Florida. Propagation: Like most citrus species and cultivars, including (surprisingly!) many hybrids, Rangpur lime comes true from seed. Most citrus species and cultivars have polyembryonic seeds; that is each seed gives rise to two or more seedlings. The seedlings are genetically identical to the mother tree. The citron (Citrus medica), pummelo (C. maxima), 'Temple' tangor (C. X nobilis) and 'Clementine' mandarin are exceptions: they do not come true from seed.
Rangpur lime was formerly used as a rootstock for commercial citrus, but trees budded onto it tended to be short lived. The juice, a complex flavor reminiscent of tangerine and lime, is sometimes mixed with mandarin juice to give it a little more kick. The leaves are very aromatic and remind me of kaffir lime (C. hystrix) and surely could be substituted for that flavor in Thai recipes. It is reported that an excellent marmalade can be made from Rangpur lime, but if you've ever tasted Ruthie Belle's lime pie, you wouldn't use the fruits for anything else!
Ruthie Belle's Famous citrus pie:
Beat 3 egg yolks in a mixing bowl.
Add 1 can Eagle Brand sweetened condensed milk
Add 1/2 cup fresh squeezed juice
Add another can condensed milk and another 1/2 cup juice and blend.