This is a picture of the Opuntia in my front yard...I'm going to make jelly with the hundreds of fruits this year. It goes right through the freezes we have in the Winters here, which I know are nothing like yours in Romania. They get leggy and stretch really fast if they don't get tons of sunlight. Do you ever use growlights?
The cool thing is they can be kept smaller, beautiful and bushy in containers with paddle pinching