Antenocitis Workshop Ltd is an established scenic supplier to the wargames industry who produces some interesting products many of which are suitable for use in dioramas.

One of their products is a range of "leavers" which are miniature leaves similar to those produced by some other companies such as Hudson & allen and Diomaster.

Antenocitis, however, have colours of brown, light green and dark green. What is different about these leaves is that the individual leaves are painted (yes painted) with an acrylic paint that means they are UV resistant and colourfast.
The packages contain many whole leaves and some crushed leaves and make for very realistic scale leaves as the colouration is never uniform and thus extremely natural. They have also told me that they can make custom batches/colours although there is a minimum order volume. Prices are £4 for the natural brown and £5 for the coloured varieties, the bags are larger tha the H&A bags and they go a very long way