acually it looks small like this^^ but is turning color. I doubt this 'Japanese Orange" is the same as what your parents have..it is really a citrus relative(poncirus)..it is not actually a true citrus. It comes actually from China..loses it's leaves over the winter(deciduous)..and is hardy to -15 to -20 below zero Fahrenheit!!!!. The 'oranges' are VERY bitter and can only be used for seasoning or a very strong lemonade(with LOTS of sugar). This plant is not even supposed to grow here..and certainly not produce fruit..which is why I am so pleased with it.
more pics of Poncirus:
*just went out in the cold and drizzle and took some pics while it is still there and not destroyed by some animal/human*