I reallly need to try Henna. I keep saying it and really not doing anything about it. But, your story has peeked my interest. I'll start looking at the brands and jut dive into it without thinking of the process
You should probably do a little research first. I'll help.
For example, never buy the pre-boxed stuff (e.g., Light Mountain Natural), which contains metals and can turn hair ends green. What you want is a body-art quality, finely sifted henna.
There is also a bit of an art to curing the paste and different results, depending on how long you leave it in your hair.
SusieQ, if you start a henna thread, I will happily post my experience (as well as my mistakes so you don't have to live through them), and I can post links to the best resources on the web.