Yuzu is a Japanese citrus tree (Citrus junos). The yuzu tree is a hybridisation of a sour mandarin and the lemon-like Ichang papaeda. An essential element of Japanese cuisine, yuzu is used to flavour ponzus, soy sauces, miso, honey and chilli paste. European chefs have embraced its famously tart juice in dishes as wide ranging as fish and white meat to sorbets, ice creams and cheesecakes. Yuzu juice and zest are also big hits with the cocktail crowd and a yuzu gin & tonic tastes like discovering the drink all over again for the first time.
Genuine, un-grafted yuzu trees are hardy down to -10ºC but take over 10 years to yield fruit. Yuzu trees are often grafted onto faster growing root stock so this will dictate it's hardiness, The Wasabi Company sells fruiting yuzu trees that are hardy down the -5ºC.
Genuine yuzu trees take 10 years to yield fruit, grafted trees from The Wasabi Company are sold at 2-3 years old and will yield fruit this year or next.