The flower itself didn't so much bloom after being frozen, as cultivated tissue was worked in vitro to produce a viable flower. It's not exactly clickbait given the payoff, but it's still less than truthful IMO.
I guess I automatically assumed it was a human-assisted process since the link was to nature.com, although in hindsight it would have been equally publishable, if not more so, if the flower bloomed on its own.