We should take from Sufis what corresponds to the teachings of Islam both in theory and practice. The early Sufis set good examples in sticking to the teachings of Islam as conveyed by the Qur’an and the Sunnah. However, the act referred to in the question has no basis in the Shari`ah. In addition, there is no specific significance for the colors red and green, and describing them as holy colors is a baseless claim that has no backing.

Sheikh Ahmad  Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states the following: Opinions such as the not wearing certain cloth colours are not based on any evidence from the Shari`ah. Part of the problem could be deficient knowledge of the Shari`ah. It has been reported that Imam Malik said, “Whoever becomes a Sufi without proper grounding in fiqh, he will become a heretic; likewise, whoever becomes a faqih without imbibing the Islamic spirituality (tasawwuf) will also become a heretic.”

So do not follow those who are deficient in the knowledge of the Shari`ah. The authentic tasawwuf is based on strict teachings of the Shari`ah. This is because all of the genuine scholars of tasawwuf  tell us that one must weigh each and every opinion and statement by the sure yardstick of the Shari`ah and reject everything that does not pass the test.