We don't hate all plastic at Chimney Sheep. In some cases it's a useful, durable, lightweight material. That's why we use it in our Chimney Sheep chimney draught excluders. The plastic in these is high quality, intended to be used for many years, after which it can be recycled. We've gone to a lot of trouble to make sure it's robust and long-lasting. We looked at other materials and plastic ticked all the boxes of being strong, lightweight (so it doesn't pull the 'Sheep out of the chimney), affordable, replicable, and manufacturable.
However. Plastic in the countryside or in the garden is another matter. As you know it lasts many hundreds of years before it gradually biodegrades, producing micro-plastics en-route. It's a bit pointless having pegs that last forever to peg out mulch mats that last one or two years. So we cast about to find something suitable, and there it was: food use bamboo skewers! This type with a little knot at the end is perfect for pegging out the mat and holding it flat. What we find is that once it gets wet, and grass underneath sort of grows into it in an attempt to get through, it makes it adhere to the ground and the material it's mulching contributes to the mulching properties of the mat.
Simply arrange the mat around the base of the tree. You may need to stamp down any weeds or grass that's already protruding. If it's long don't bother to cut it, just trample it down. Then peg each corner down with a bamboo skewer. There are 40 in a pack, enough to go with up to 10 of our 100cm x 100cm mulch mats.