Question
I live in Doncaster, South Yorkshire.
We transplanted a large Mimosa plant from its pot into the garden a few months ago because it was somewhat too big for its pot and kept on blowing over by the wind.  It has recovered well from its transplant, and was showing good signs of new growth.  Today, disaster, my husband was painting the outside of the house and his ladder
fell down slicing a good chunk of the Mimosa away.   There is still 3/4 of the tree left but of course the trunk has a slice out of it.  Is there something we can do or something we can apply to the trunk to aid its recovery and avoid disease please?   Thanks in anticipation.  

Answer
The best thing to do is prune off the dead or broken off branches and the slices of bark near the wound. The tree will heal over without anything put on the wound. If it had been earlier in the year I would have recommended an insecticide spray to prevent insect attack but this time of the year it is not needed.