All trees do best if planted in the winter, but sometimes it can be too cold.
When is it too cold to plant new trees?
If there is a cold-snap and overnight temperatures are well below freezing then it is likely to be too cold to plant. If you cannot dig a hole because the soil is frozen below ground level then it is definitely too cold to plant.
Conversely, if overnight temperatures are only just below freezing, and daytime temperatures are averaging 5C or so, then the ground probably won't be frozen (perhaps just lightly frosted) and you can go ahead and plant.
If you have lying snow then it is usually possible to plant, as the ground will probably not be frozen.
How to store pot-grown trees
If you have received a delivery of pot-grown trees the best thing to do is unpack them and place them in a frost-free shed or garage. They can be left outside if necessary, but try to insulate the pots with sacking or newspaper.
How to store bare-root trees
Bare-root trees should normally be planted out immediately you receive them. If it is too cold then they need to be "heeled-in". This basically means removing the packaging, lying them on the ground, and covering the roots with soil.
You can also lie them on the ground in a cold garage or shed and cover the roots with compost, or put the roots in a bin liner and fill it with compost.
See our article on heeling-in fruit trees for more details.
When is the best time to plant new trees
Any time between December - January is the best time to plant both bare-root and pot-grown trees, ideally when the weather is mild can quiet.
Don't water the trees if the ground is freezing or overnight temperatures are going to be below freezing.
Under no circumstances attempt to keep new trees in a heated house or conservatory - this is an easy way to kill them!