Question Summary:
Regarding the Ghusl of women and washing the hair

Question Detail:

this question is regarding the ghusl of women and washing the hair, I am aware that if a woman has a plait in her hair then it is necessary for the roots to be washed, without opening the plait, is ghusl still counted if the plait is left dry and only the roots are washed?

Answer :

If water reached the roots of the plaits of the hair, that is sufficient even though the plaited hair remains dry. However it is advisable to make water reach the plaited hair. [1]
And Allah Ta’āla Knows Best
Student Darul Iftaa 
Zakir Husain
Michigan USA
Checked and Approved by,
Mufti Ebrahim Desai.
[1]
وَلَيْسَ عَلَى الْمَرْأَةِ أَنْ تَنْقُضَ ضَفَائِرَهَا فِي الْغُسْلِ إذَا بَلَغَ الْمَاءُ أُصُولَ الشَّعْر لِقَوْلِهِ عَلَيْهِ الصَّلَاةُ وَالسَّلَامُ لِأُمِّ سَلَمَةَ رَضِيَ اللَّهُ عَنْهَا { أَمَا يَكْفِيك إذَا بَلَغَ الْمَاءُ أُصُولَ شَعْرِك } " وَلَيْسَ عَلَيْهَا بَلُّ ذَوَائِبِهَا هُوَ الصَّحِيحُ ، بِخِلَافِ اللِّحْيَةِ لِأَنَّهُ لَا حَرَجَ فِي إيصَالِ الْمَاءِ إلَى أَثْنَائِه[فتح القدىر ج١ ص٩٥ ]
وَقَالَ فِي الْوِقَايَةِ وَلَيْسَ عَلَى الْمَرْأَةِ نَقْضُ ضَفِيرَتِهَا وَلَا بَلُّهَا إذَا ابْتَلَّ أَصْلُهَا .
قَالَ صَدْرُ الشَّرِيعَةِ وَقَوْلُهُ وَلَا بَلُّهَا قَالَ بَعْضُ مَشَايِخِنَا تَبُلُّ ذَوَائِبَهَا وَتَعْصِرُهَا لَكِنَّ الْأَصَحَّ عَدَمُ وُجُوبِه[ِتبيين الحقائق ج١ ص٦١ ]