A_low growing mint which makes a wonderfully scented ground cover._Cunningham mint is a sort of pennyroyal and has_the same very clean, minty aroma. It makes a bright green carpet but tends to die back in the winter and is a bit slow to recover. But by spring it is as green as ever. Cunningham mint being related to pennyroyal is not a herb to be taken internally as it has toxic properties but over many years it has been found to repel fleas and other unwanted insects. It is used in flea collars for cats and dogs and is probably effective as a moth repellent.