The rose garden was originally a private garden belonging to a wealthy old lady. The old man loved roses before he was alive, and he made a will and donated the rose garden to the government. Although the garden is not large, the surrounding environment is beautiful, and it is a good place to talk about love.
The Parnell Rose Gardens is a section of land given over to roses. It's not a formal attraction with an entry fee. Just walk into the gardens, which aren't walled off. Remember that roses bloom during the summer, so you might skip this if it isn't between October and April.
In the private garden, roses are vying for beauty, and you can't feel that it is in the severe winter!