A spreading, prostrate perennial with small, elliptical grey green leaves. Its spreading form makes for a mound and in summer to autumn it produces upright spikes of white to lilac flowers.
Pennyroyal is excellent for repelling insects, especially fleas, so if you have dogs then get some of this pant into your garden. It is also good against ants.
Mentha pulegium is often used in companion planting in vegetable gardens as it will repel a lot of pests.