What makes mint cool

Mint is a gift in any garden, in all its gloriously fragrant forms – just don’t plant it in open ground, says Monty Don

Mint is wonderful to have growing in the garden. Fresh peppermint makes a soothing tea that is ten times nicer than anything that comes in a tea bag, however well prepared. Spearmint is perfect with all dishes that call for a minty tang, and apple mint transforms the humble potato into a feast. Should the fancy take you, there are eau- decologne mint, pineapple mint, chocolate mint and banana mint to add to your collection.

But – and this is one of the really big horticultural ‘buts’ – growing mint in open ground is likely to end, if not in tears then at least with extreme compromise.

Last year, as part of the new herb garden we have been making in my Herefordshire garden, I prepared five squares of soil (which had previously contained large box balls, now removed as a result of box blight) surrounded by cobbles set into sandstone. For sandstone read rock. Solid rock. Into each square I planted half a dozen mint plants, with two squares devoted to peppermint, one to spearmint and two to apple mint. My thinking was that each would grow in these pockets of soil as though they were in a container.

I could not have been more wrong. After three months runners were spreading sideways, and after six months popping up through the sandstone and out into the path some yards away. Mint is a voracious spreader and will find a way to grow sideways until it hits a barrier. In practice, if you grow mint in a border it will eventually become a mint border because nothing else will have a chance to establish.

So the solution is to always grow it in a container of some sort. Not only does this solve the problem of global mint takeover, but it also means that you can position the pots where you want them – and just outside the kitchen is usually the best place. It looks good and, of course, smells wonderful, too, so having a pot growing where you can pluck a leaf when you pass means you can release that lovely fragrance.

All mints do best in a sunny position with good drainage although, as I have implied, they will grow almost anywhere. When I plant them in a container I mix one part grit or perlite with two parts peat-free potting compost, one part sieved garden compost and one part garden soil. This provides them with the nourishment to sustain repeated picking and limited root run. A really good soaking once a week is always better than a daily sprinkle. It is a good idea to repot your mint every autumn to encourage maximum leaf growth the following year.

All mint will set flowers and the leaf production will dramatically decrease in both quantity and quality from midsummer onwards. The solution is to cut them back very hard in July, water and feed with liquid seaweed – tender new growth will appear about four weeks later. To keep a constant supply I have a number of pots and cut them back in sequence so that we are never entirely without fresh leaves.

Never plant different types of mint in the same container as they will hybridise and you will end up with diminished flavours. So instead of one large container with three or four types, have three or four pots each with a single variety.

Mint does not come true from seed (other than pennyroyal, Mentha pulegium) so it is best to propagate it by either taking cuttings from non-flowering growth in late spring and early summer, root cuttings in spring or simply dividing and replanting existing established plants.

Monty with his peppermint