Is it too late to plant perennials after first frost?

Hi all. I’m looking to plant some more hardy perennials as autumn is generally the best time to plant, however I’m considering whether the minor frost we had recently could mean it’s no longer a good idea.

This was a very mild one, and the upcoming weather shows no signs of frost at all. I imagine the ground is still pretty warm too. I’m just wondering what all of your thoughts are about this.