I'm firmly wedded to the ground foam and PVA method of scenic ground cover. I'll tend to use any of the major producers: Woodlands Scenics etc, but add a few home-brewed products to the mix. Mrs F. occasionally has a green tea moment and I'll quickly harvest the bags, tip the contents onto a plate and leave on a warm window sill to dry thoroughly for a week or two. This has the added wind-up factor as when Mrs F's posh friends turn up and ask, 'what's that?' Pointing at the plate. I just reply knowingly 'Special leaves...' change the subject and wait for the looks between them.