Q.Winter care for 4 year old 0RANGE TREE
The orange tree was bought 3-4 years ago as a potted plant. It did not `do` much for the first year so we decided to put it in the ground. Since then it has grown and thrived and last year we had 3 oranges ..the majority fell off when very small. This year we have over 30 oranges, some very small, some about the size of tomatoes and 2-3 more like the size of a tangerine. They are all green and we presume that if they survive the winter ,when uncovered next spring, they will increase their size and develop their orange colour.
We cannot track down a protective bag big enough (the foliage is approx. 4ft x3ft ) would to`bandage` with floss be enough protection?

You may want to remove the small fruit from your young tree. This will help your tree use it's energy in putting down roots instead of fruit.
https://www.gardeningknowhow.com/edible/fruits/oranges/growing-an-orange-tree.htm
https://www.gardeningknowhow.com/edible/fruits/oranges/pruning-orange-trees.htm
https://www.gardeningknowhow.com/edible/fruits/oranges/harvesting-oranges.htm