tenant asking for upgrades after moving out

[Craig Sutta]

my tenant improved our garden before leaving. He is claiming me to pay him $3000 for yard upgrades!!

Last year he was not maintaining yard, and it was in bad condition. All I had done was send him email to take care of garden. He works for lawn company and himself told verbally that he got material for free. Then he worked in lawn himself to make upgrades.

he was not maintaining our home from inside either, so i asked him to leave & he is claiming he improved yard but never enjoyed it because i asked him to leave.

He never took permission to put yard stones, now he is asking me to pay up. I have tried to speak to him to discuss but he has refused to talk and wants to communicate only through emails in writing. 

now that he has left, can i deduct security deposit for cost of removing the boulders/ stones from my yard? I am shocked how is he asking me to pay instead?