Mint

Origin & history

Peppermint is not a wild species but a natural cross between water mint and spearmint, spotted in England around 1696 and afterwards grown as a field crop at Mitcham south of London — “Mitcham” still stands for peppermint today. Being a hybrid it is sterile and sets no viable seed, so every peppermint plant in the world comes from vegetative propagation. The rest of the genus, by contrast, crosses readily, which explains the many intermediate forms in the trade.

Varieties

“Mint” is an umbrella term for dozens of species and varieties. For tea and for Middle Eastern cooking you want spearmint or Moroccan mint (Mentha spicata) — mild and sweetish, without the menthol bite; peppermint is the sharp, cooling one. Then there are the scented varieties such as chocolate, strawberry or orange mint. Buy plants, and buy by smell: rub a leaf, because mint labels are notoriously unreliable, and a seed packet marked “peppermint” will necessarily give you something else.

Care

Mint is the one kitchen herb that does not want to stand dry: evenly moist, in partial shade, and in a pot watered almost daily in summer. As soon as the first flower buds appear, cut the whole stand back to a hand’s width — the second flush gives large, soft leaves again, whereas flowering shoots give only small tough ones. In a pot or behind a root barrier the soil exhausts itself quickly; divide the clump every two or three years, discard the spent middle and replant the strong outer pieces in fresh soil.

What can go wrong

Mint rust is the classic: orange-brown pustules on the undersides of the leaves that spread fast in summer. The fungus overwinters in the rootstock, so cut affected shoots right off and put them in the household waste rather than the compost, plant more airily, water at the base rather than over the foliage — and if the attack keeps coming back, start again with healthy young plants in a new spot. Dense old clumps add powdery mildew towards the end of summer; a radical cutback usually deals with both. A pot that is too small is the second commonest reason for small, tough leaves.

Harvest, storage & kitchen

Mint has most flavour just before flowering; cut whole shoots then instead of picking individual leaves. It is one of the few herbs that loses almost nothing when dried — dry it in bunches somewhere airy and shaded and keep it dark in a well-sealed jar. Fresh spearmint suits yoghurt, peas, potatoes, couscous and cold drinks; sharp peppermint is usually too dominant for that and is better kept for tea.

Frequently asked questions

Is mint winter hardy?

Yes, without reservation. The top growth dies off in autumn, the rootstock sits out the winter in the soil and new shoots appear in April. Only in a pot is the rootball at risk, so stand it sheltered by a wall on a board, not in a warm room.

When do you plant mint?

From mid-April to mid-June, 30 centimetres apart, in partial shade and soil that does not dry out. Picking runs from mid-May to mid-October. A piece of root from somebody else’s garden establishes just as reliably as a bought plant.

Can I harvest mint while it is flowering?

Yes, the leaves remain edible, though during flowering in July and August they are smaller, tougher and a little more bitter. The pale violet flowers are edible and popular with bees, so leave a flowering shoot at the edge.

How do I stop mint spreading through the bed?

With a root barrier set 30 to 40 centimetres deep and standing five centimetres proud of the soil, or the runners simply travel over the top. A pot with no soil contact holds it back just as reliably, and escapees can be sliced off in spring.