All answers are the names of trees and shrubs:
Military home for a merry man in green (5,3)
Improve this by beating, along with a woman and a dog (6)
These have religious associations:
Celestial specimen (4,2,6)
Specimen of suffering (5,2,6)
It's a little rhyme, along the lines of - a woman, a dog and a walnut tree - the more you beat them, they better they be.
Folks used to thrash walnut trees with a chain 'to make the sap rise' or or something.