Mint

Light and exposure

Mint grows in sun as in part shade, and in a temperate climate it even appreciates a slightly shaded position that keeps the soil cool. In full sun it demands more water so as not to wilt during the hot hours.

In a pot, place it in a bright spot without scorching sun all day long. A cool corner of the garden, against a wall that catches the morning sun then falls into shade at the hottest hours, suits it perfectly and spares it from suffering in summer.

Watering

Mint likes moisture, it is a plant of cool places. Water generously and regularly so the soil does not dry out, or you will see the foliage wilt and the stems go bare at the bottom.

In a pot, watch it constantly in summer: the substrate dries fast and a thirsty potted mint declines quickly. It is one of the few aromatics that tolerates a truly moist soil, provided it is not permanently waterlogged.

Soil and repotting

Mint is not fussy about soil, it thrives in ordinary earth, cool and rich in organic matter. An addition of compost in spring boosts the production of tender stems.

In open ground, its running roots shoot off in all directions. To contain it, plant it in a large sunken bottomless pot or in a well-defined area. In an above-ground pot, repot or divide every two or three years, because it quickly exhausts its substrate and coils around itself.

Temperature and humidity

Mint is a fully hardy perennial, rated USDA zones 3 to 9 depending on the species. It comes through damp winters with no protection at all: the aerial parts vanish at the first frosts, but the crown and running roots overwinter underground and start up again in spring with renewed energy.

This hardiness is total, cold does not threaten it. A plant established once returns every year and spreads a little further. In a pot exposed to frost, a very small container can freeze right through during a harsh winter: in that case, a slightly larger pot or one placed against a wall is enough to protect the crown. In open ground, no worries at all.

Pruning and upkeep

Harvest by cutting the stems above a pair of leaves, the plant branches out and stays bushy. Regular pruning stops it shooting up and going bare. Cut a tired clump back hard, it comes back with new, more fragrant leaves.

Remove the flower stems as soon as they appear if you want to favour the foliage: once in flower, mint slows its production of tender leaves. At the end of the season, cut the whole clump back close to the ground, it will come back clean in spring.

Pests and diseases

Mint rust, Puccinia menthae, is the most common disease in a humid climate: bright orange pustules appear under the leaves, then the stems distort. Cut off and dispose of the affected parts without composting them, and in the event of a severe attack cut the whole clump back to start again on healthy growth.

Powdery mildew can also felt the foliage white in mild, damp weather. To limit these troubles, aerate overly dense clumps, avoid wetting the foliage in the evening and divide the plants regularly so they do not pile up.

Propagation

Mint propagates effortlessly. Dividing the clump in spring or autumn is the simplest way: dig up a piece of crown with its running roots and replant it elsewhere, it takes at once.

Cuttings are just as easy: cut a ten-centimetre stem, strip the lower leaves and place it in a glass of water. Roots appear within one to two weeks. A simple fragment of running root laid on moist soil is even enough to produce a new plant, which explains its invasive side.

Month-by-month care calendar

Green Hub tips

• Always plant mint in a pot, a tub or a sunken bottomless container: in free open ground, its roots invade the whole bed.
• Cut a tired or rust-hit clump back hard, it comes back with new, more fragrant leaves.
• Express cuttings: a stem in a glass of water roots in two weeks. A fragment of root laid on moist soil is enough too.
• Divide the clump every two or three years. As it ages, mint piles up, exhausts itself and catches rust more easily.