"when the gorse is out of bloom, then kissing's out of fashion"
Luckily more than one species of gorse grows in the UK. The Common Gorse or Furze flowers in the spring and is flowering now. It will continue until early summer when the Dwarf or Summer Gorse comes into bloom continuing until the start of winter. This covers most of the year but there are always a few flowers on gorse bushes all through the winter so I don't think kissing will be losing its popularity anytime soon!
Happy Valentines Day.