First, thank you for caring for these cats.
There are treatments for the grass, but I believe the first step should be treating the cats. I would recommend a humane trap, and a flea treatment applied to the cats' backs. Of course you would need strong gloves, but I think you could manage to apply Advantage to the back of the neck. Then, make certain that you use a flea treatment on the grass that is safe for cats. I found a number of products on Google. However, all of the sources I found recommend treating the cats first. Good luck.
There are feral cats that go wild in a humane trap, so Feliway might prove to be useful. You could also consult a vet or the Humane Society, and ask for help.
Are these cats neutered? If not, low cost spaying and neutering are available, and the cats could be treated while under anesthetic. Good luck!
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
A dog, I have always said, is prose; a cat is a poem. ~Jean Burden