well, my hair is down between my shoulder blades, which while not your length, would lead me to believe that
it works for all lengths and thicknesses - I think the key is to use an aerated dispenser - you know the ones which
make liquid hand / dish soap "froth" ... I noticed I was better able to wash my hair thoroughly once I switched to
this type of dispenser.

Also, you can add other dried/fresh herbs to the boiling mixture or essential oils, afterward ,to enhance its cleaning
ability and, of course, to suit your hair / scalp type.

I add fresh rosemary from my window box and usually an essential oil to suit my aromatherapy needs. It works well
because you can really only make small batches; each lasting about a week or so. Every couple of weeks I make
a different concoction / scent. This week I'm on a lavender / sweet orange "kick".

Oh and lastly, if you have room to grow it, I'm told it propagates really well - I don't so, I buy. oh well! :)

Cheers!