The former Werder Bremen defender had an offer from Stuttgart retracted, before he was turned down by Tony Pulis despite a successful trial period at the Britannia Stadium
The left-back departed Werder Bremen as a free agent at the end of the season before representing his country at Euro 2012, where they were knocked out at the group stage.
However, despite impressing during a trial with the Staffordshire club, the 25-year-old has now been left without a club for the new season.
"I won't do that again," Boenisch recalled to kreiszeitung.de of the trial.
"I played in two friendlies and the coach [Tony Pulis] told me that I had been one of the best - but he could not buy me because he had to sell two defenders first.
"That's when I asked him if he was joking with me. England is just strange."
Boenisch also revealed he had been closing to joining Bundesliga outfit Stuttgart but could not leave Poland's European Championships training camp.
"Stuttgart wanted to finish the deal very fast," he explained. "I was told to fly in for a medical but I couldn't because of the extreme doping regulations during the Euros. You are not allowed to leave for several hours."
When asked why the German side subsequently withdrew their offer after the Euros, he replied: "I still don't know why.
"Sometimes I ask myself: 'A few weeks ago I played in the Euros and now I don't have a club – how can that be?'," he mused.