ingredients & tools:
Paper tissue or cotton wool,
a cheap plastic container (not too deep),
rubber gloves,
toothpicks or similar
white/ pva glue
a bit of water
appropriately coloured paint
(optionally fine turf)
Prepare your mixture of white/ pva glue + a bit of water + paint in the plastic container.
Put on your gloves.
If you use paper tissue, cut it into thin strips and soak it in the mixture. If you use cotton wool, pull it apart a bit and soak it in the mixture. Pick up the cotton wool and squeeze it a bit to remove most of the excess liquid.
Put the wet cotton wool blob on a suitable surface (e.g. and old place mat) and use your finger (and the toothpicks for finer strands) to pull the cotton wool apart a bit more.
Drape over your scenery bits and let it dry.
Additionally you could add some fine turf to make it look more plant- like.
Cotton wool does works better imho for a strandy look, tissue paper works better for something remotely leafish looking.