In the name of Allah, the most Beneficent, the most Merciful.
Answer
If the womans’ hair is braided or is in a bun then ghusl will be valid as long as one is certain that the water reaches the roots of the hair. (Maraqi Falah p.42)
With regards to ribbons, elastic etc it will be necessary to take them off, as it is compulsory that water must reach every portion of the body including the hair in an obligatory ghusl.
Only Allah Knows Best
Mohammed Tosir Miah
Darul Ifta Birmingham