Lartey remained on the floor before being helped onto a stool safely when he spent a further few minutes recovering.
British boxing great Tony Bellew took to Twitter to show his amazement at the win for Wardley, calling it a "statement".
Wardley told The Sun after the bout, he was happy with the result that 'answered questions about his punching power'.
"I can hang with the big boys. I just proved that when I sit down on my punch, I can get you out," he said.
"I'm moving at a good pace. Decent opposition. Lartey was a good challenge that I passed easily.
"I still need to build and learn. I haven't gone to the second half of a fight or got into a war."
Wardley now has a 10-0 professional record, with nine of those wins coming via knockout. He currently holds the English heavyweight title.