Growing conditions involve freezing -5 -7 in the greenhouse.
There was a question of finding a suitable citrus rootstock that tolerates cold, loam, lime
Poncirus very good cold-resistant rootstock, but it chlorotic in lime soil.
Sweet orange can not stand the cold and heavy clay soil
Citrumelo the Dunstan first year gave good gains, but then root came into lime and autumn growth was chlorotic
Here is a tree-based garden citrumelo the Dunstan
The largest increase in Mandarin karaji, after a week of night frosts -8 in January 2017 no damage