I think it’s because they are a setting where people are there for a separate purpose to meeting a partner, which allows for romance to be portrayed as spontaneous. Also, clothes (particularly underwear, pyjamas and towels) come into contact with the body and imply intimacy.
Hedges are a good investment because once it has matured a hedge provides food and shelter for many species of birds, animals and insects. There are government subsidies available for establishing and maintaining them. They also provide returns for people in the form of wood and in some cases edible fruit.