Mint, That Delicious Invader

Anyone who has ever grown mint in their garden is well aware of its propensity to spread far beyond the space you’d like to allocate to it. Fortunately, there is a strategy for growing and enjoying this delicious herb without the risk of overgrowth.

Mint in a Nutshell

Most mints are native to Europe and Asia. They have been used as culinary and medicinal herbs since Antiquity.

There are several hundred mint species and cultivars on the market. Some have been developed for their scent and flavor, others for the ornamental aspect of their foliage. Some mints are very pungent, while others are rather sweet, but all contain the characteristic essential oil: menthol. This natural product or its synthetic version is widely used in the food and pharmaceutical industries. Think of toothpastes, candies, chocolates, lozenges and syrups. Mint has long been known to aid digestion and soothe coughs. But that’s where my expertise in the medicinal virtues of mint ends.

Varieties and Hardiness

Are you tempted by the subtle flavor of chocolate mint to make herbal teas, by mojito mint to make… mojitos or by variegated apple mint just for its beauty? There’s no shortage of choice in garden centres. However, your selection should also be dictated by the hardiness of the chosen variety. For example, spearmint is hardy in zone 3 (4 USDA), while variegated apple mint is classified in zone 6 (5-9 USDA). Fortunately, most other mints are hardy to zone 4 or 5 (3-11 USDA).

The two most common mint varieties are spearmint and peppermint. They are distinguished by the presence or absence of petioles on their leaves. Peppermint leaves are stalked, while spearmint leaves are sessile (stalkless). They are also fuzzy.

Trois raisons qui expliquent l’envahissement de la menthe

Of all herbs, mint takes the prize for its ability to adapt to different growing conditions. Whether the soil is rich, poor, dry or damp, and whether the sunshine is maximum or reduced, mint usually manages to make a permanent home for itself.

But it’s above all the fact that mint is equipped with rhizomes and stolons, whose ability to multiply is highly efficient, that makes it one of the champion plants of invasiveness.

Mint plants have rhizomes, underground storage organs that proliferate horizontally, producing roots and stems every year. What’s more, a little like a strawberry plant, when the large stems (stolons, in fact) of mint touch the ground at a node, roots develop to produce a new plant. This is a natural method of propagation: layering.

These characteristics mean that mint can become a real nuisance. No wonder it’s banned from some community gardens.

Two Strategies to Avoid Invasion

I grow a dozen varieties of mint in my urban garden. To prevent my plants from turning into weeds, here are the two strategies I’ve successfully adopted over the years.

Firstly, I systematically plant each plant in a plastic pot buried in the soil. To do this, I use large nursery pots in which trees or shrubs are sold. Although many pot sizes can be used, I prefer those that are at least 30 cm (12 ») in diameter and high. To install my system, I dig the hole to a depth less than the height of the pot. I fill the pot with the soil I’ve collected, then place it in the hole so that it protrudes 3 to 5 cm (1-2″)above the ground. Finally, I plant the plants.

Then, throughout the season, I take care to harvest regularly by trimming the ends of the long horizontal stems, to prevent them from touching the ground and taking root.

After three to five years, you’ll notice that the plants tend to clump together at the edges. At this point, it’s a good idea to regenerate the plants so that they retain good vigor. To do this, remove the plant from the pot and prune off any damaged parts. Then enrich the soil with compost and replant the plant in the center of the pot.

Growing Mint in Pots

Like most herbs, mint is well suited to growing in pots, as it is more exposed to heat. However, to maintain vigorous plants, you’ll need to make sure that mint doesn’t run out of water. So it’s always wise to opt for large pots, which have a better water reserve.

While heat is an advantage in summer, cold is a limiting factor for mint survival when exposed to winter cold. Geotextile bags and wooden tubs are good choices, as they drain well. But an unfailing tactic is to choose very hardy varieties and place the pots in a location where snow can be expected to cover them during the cold season.

Harvesting and Storing Mint

Once the mint plants have reached 15 cm (6″),you can start harvesting by pruning the stem ends. It’s a good idea to do this on a regular basis, to prevent the stems from layering. It also allows the plants to grow denser.

My favorite way of preserving mint is to dry it in bunches. This involves tying two or three stems together with an elastic band, then hanging the whole thing in a dry, well-ventilated place, while avoiding direct light. This can be a taut rope, a coat hanger or a hook. Once the leaves have dried, remove them and store them in an airtight container away from light.

Whole or chopped leaves can also be frozen, after being placed in ice cube trays and covered with water.

Use in the Kitchen

While in North America, mint is most often used in herbal teas and desserts, it is an integral part of many dishes around the world. Mint can be used in dips, butters and sauces, among other things. Here’s a simple and delicious recipe from my book “Les fines herbes de la terre à la table”, created by Marie-Lou Roy.

Tzatziki With Mint

• 1 cup Greek yogurt
• 1 clove garlic, minced
• 1 medium cucumber
• 1 tablespoon lemon juice (or cider vinegar)
• 2 tbsp. chopped fresh mint
• Salt and pepper to taste

Peel, core and grate the cucumber. Place in a colander with a pinch of salt and leave to drain for 15 minutes, then squeeze out as much water as possible. Mix with remaining ingredients.

On that note, I hope you enjoy this delicious invader.