US 852

A cross between Changsha mandarin and Poncirus 

1/2 Poncirus, 1/2 Mandarin

Citrus reticulata 'Changsha' x C. trifoliata 'English Large Flowered'

Crosses between mandarins (satsumas) and hardy oranges are called citrandarins.  Citrandarins are some of the hardiest 50% crosses because of the cold tolerance of the mandarin, and Changsha is one of the most cold tolerant of all mandarins.

It was developed as a citrus rootstock.  Patented and released in 1999.  It is Phytophthora resistant, Nematode resistant, and has superior yield when compared to most other rootstocks.

It has fewer seeds per fruit than is desired for a rootstock and about half the seed is zygotic, i. e., does not come true. [1]
Fewer seeds per fruit and zygotic nature of some seedlings have piqued the interest of people looking to grow more cold tolerant citrus. 

A zygotic seedling or mutation of US 852 growing in Northern Virginia [2]  withstood 0°F, -18°C [3], it died to the ground in the severe winter of 2014-2015, it did resprout from the roots.  There was one several years old in Philadelphia, and at least one is grew in New Jersey.  The Northern Virginia tree has almost no Poncirus bitterness [5]

Seedlings of US 852 or from a similar cross [8] are growing in Europe, labeled HRS 899 [6][7]  They have been labeled HRS 899 a, b, c, etc.  They have varying degrees of hardiness, leaf shape, and taste.

Leaves are attractive, shape is distinctive, center leaflet has a longer center than other trifoliate hybrids.   Leaves are also thicker than most citrus and have crenulate margins.

Some spines are long, over 4"or 10 cm in length, but thinner than Poncirus. 

Picked first fruit in November 2016.  Fruit were puberlulent (faint fuzz) from Poncirus parent.  High sugars and high acidity, pronounced bitterness from Poncirus.  When diluted and sweetened like lemons are able to make a pleasant tasting  'ade'.   Brix 14, sour similar to lemon.