black habit …

Canon XLII. Those who are called Eremites and are clothed in black robes, and with long hair go about cities and associate with the worldly both men and women and bring odium upon their profession—we decree that if they will receive the habit of other monks and wear their hair cut short, they may be shut up in a monastery and numbered among the brothers; but if they do not choose to do this, they are to be expelled from the cities and forced to live in the desert (ἐρήμους) from whence also they derive their name.

Council of Trullo (692)

Hermits who were not monks have tended to keep both beards and hair uncut, although there have been and are exceptions. This has been based less on any specific prescription relating to hair rather than

• following the tradition and practice of the earliest Hermits;
• as a sign of lack of interest in or concern about physical appearance;
• to minimise the need to pay attention to personal adornment through regular shaving and/or hair cutting;
• as a reaction against worldly fashion (although this has raised some concerns at times when beards and/or long hair were the height of popular fashion!).

Hermits and Hair