Mint: propagation, overwintering & more

Sebastian
Sebastian
Sebastian
Sebastian

As a horticulture student I mainly studied crops and cultivation techniques. It fascinates me how many diverse plants can grow from small, nearly identical seeds.

Favourite fruit: blueberries, grapes, raspberries, pears
Favourite vegetables: mushrooms, peppers, kohlrabi, onions, garlic

Mint is a well-known aromatic herb that is commonly used in drinks and desserts. Find out everything you need to know about overwintering and propagating mint.

Mint plant
Mint has been cultivated for several centuries [Photo: AP focus/ Shutterstock.com]

Around the year 800, Charlemagne decreed four species of mint to be planted in his empire’s gardens, among other things. Mint, on the other hand, has not been forgotten and is still grown in many gardens today. Read on to learn how to overwinter the herb, how to propagate it and whether mint is poisonous to pets.

Mint: origin and characteristics

The mint genus (Mentha) includes more than twenty different species. As labiates (Lamiaceae), mints are related to other famous garden herbs such as rosemary (Rosmarinus officinalis), thyme (Thymus) and English lavender (Lavandula angustifolia). Most mint species are native to parts of the northern hemisphere with temperate climates like ours.

Butterfly resting on mint flower
Mint is especially popular with butterflies, but also with other insects [Photo: photoPOU/ Shutterstock.com]

Mint is an herbaceous perennial that grows to an average height of 0.5 to 1 m, depending on the species. The inflorescences are usually false whorls, which are characteristic of labiates, as are the bell-shaped, tubular individual flowers. Depending on the species, mint flowers between May and October in white, pink, or purple. Mint flowers have a medium to high nectar value and are particularly important for butterflies. After flowering, the flowers produce seed pods, which open when ripe to reveal four individual seeds. Since mint often grows near water in the wild, the seeds are usually dispersed by water, a process known as hydrochory.

Mint leaves are egg- to elliptical-shaped, typically serrated and stand out due to their intense aroma, which varies greatly depending on the species. The plant was first cultivated over a thousand years ago to be used as an herb or brewed into a tea. Mint is a very tolerant plant that will flourish in your garden even if you have no gardening experience. Find out how to plant mint in your garden in our dedicated article.

What is the difference between mint and peppermint? First and foremost, mint and peppermint (Mentha x piperita) differ in that the term mint refers to the whole genus, whereas peppermint is only one species within this genus. Peppermint stands out from other mints due its sharper flavour.

Peppermint plant
Peppermint is one of the best-known types of mint [Photo: Allison Edrington/ Shutterstock.com]

Overwintering mint

Mint is usually very resilient to cold temperatures and requires no special protection. The herb is hardy down to -15 °C. However, to be on the safe side when overwintering mint, you can also protect it from frost. Here is how: Firstly, leave the parts of the plant that die off in autumn on the plant during winter as protection and cut back in spring. In addition, cover the plant with twigs or leaves. To overwinter mint in pots, wrap the pot with garden fleece to prevent the pot from freezing through.

Mint plant in winter
Mint is very robust and is considered hardy in the UK [Photo: Allison Edrington/ Shutterstock.com]

Propagation

As with many plants, sowing is one way to propagate mint. Although not all species can be grown by seed, mint seeds for specific species are commercially available. To save your own mint seeds, cut off the withered seeding stalks and lay them out to dry on kitchen towel or newspaper. After a few days, rub the seed heads a little to collect the seeds. Dry the seeds a little longer before storing them in a cool, dark place.

The plant also forms fleshy roots, called stolons. Dig these up after the flowering period, divide and plant in new homes. Mint often grows runners, cut these off from the mother plant as soon as they are well rooted using a spade. Then transplant to new homes and water well.

Mint rhizomes
Mint forms rhizomes that can be divided for rapid propagation [Photo: Paul Maguire/ Shutterstock.com]

If you already have a larger plant, you can also propagate it by division. To do this, cut off a section of the mint with a spade and transplant it to another spot.

Another quick and promising way to propagate mint is with cuttings. In late spring, cut off the tips of the shoots, so-called head cuttings, from the plant and put them in suitable soil, such as our Plantura Organic Herb & Seedling Compost. Mix the soil with about 20% sand to loosen it a little. If the humidity levels are high, the new mint will take root within two to three weeks.

Is mint poisonous to cats or dogs?

Mint is generally considered non-toxic to humans and animals, with one exception: Pennyroyal (Mentha pulegium). The active ingredient in pennyroyal mint is called pulegone and can cause vomiting, elevated blood pressure or anaesthetic-like paralysis by irritating the digestive tract, and in excessive amounts, death. The wild pennyroyal is considered endangered in the UK.

When using mint essential oil on pets, exercise caution because it might cause nausea and vomiting.

Pennyroyal mint plant
Pennyroyal is considered endangered in the UK [Photo: Pixiversal/ Shutterstock.com]

Did you know that you can enjoy mint all year round? Find out how to preserve mint by drying or freezing it in our dedicated article.

Plantura's Garden-Mail Newsletter