I decided to try using some Ampersand Scratchbord to see what difference there is between it (the board) and the thinner, paper style scratchboard sheets.
This was done on a 5" x 7" board and then coloured.
I used watercolour paints for the leaves (Art Spectrum Australian greens - light and dark) and then removed most of the wash leaving only a trace of colour behind.
The stems I used Derwent Inktense pencils - again, the colour was too heavy so I removed some of the colour by re-scraping along some of the stems.
The flowers were coloured using Faber-Castell Albrecht-Duhrer water colour pencils. For these, most of the colour was left on although some re-scratching was required to 'dumb down' the highlights.
The board took about a week of work with about 1-2 hours a day and then finished by spraying with Crystal Clear fixative (3 coats) to make sure the surface is preserved.
Not perfect, but the next attempt is to use a full 9x12 panel for which I have allowed myself 5-6 weeks to complete!