The midfielder collected his fifth booking of the season in Forest's 2-1 defeat at Cardiff City on Saturday.
Pearce has told the former England Under-21 international that he needs to improve his discipline.
"Henri has always had it in him to give cheap bookings away, even going to my time working with him in the England Under-21 squad," Pearce told the Nottingham Post
"It is something he has to mature a little bit, in his game, to eradicate. Otherwise he will find himself sat at home and, if somebody else comes in and does well, he will find it difficult to get back in the team."
Lansbury is suspended for Forest's match at Watford on Tuesday evening.