Mother Nature's Montrose Garden: Plant of the Month (October) : Wild Mint

Wild Mint (Mentha arvensis): Mother Nature's Montrose Garden

September is a great month for planting on the Western Slope. We’ve recently planted a number of (potentially) large shrubs in our hedgerow. We’ll tell you more on this in a later post. We’ve also added a garden ‘Plant List’ page to the blog (right). In addition to the shrubs, we’ve gotten some hardy native perennials into the ground. One of our favorites – used as a seasoning herb and tea – is the common Wild Mint, Mentha arvensis. The scientific name is pronounced MEN-thuh are-VEN-sis.

Mentha arvensis has a wide distribution. In North America, it’s native to most areas, with the exception of the deep South. But its total range includes temperate regions of Europe, as well as western and central Asia. [1] Some taxonomists separate the North American and Asian types as distinct subspecies. And Mentha canadensis (a similar species) is lumped with Mentha arvensis by some authors. We’ll see if genetic studies reveal more about the relationships of these mints.

Mentha arvensis is known by several common names, including Wild Mint, American Wild Mint, Field Mint, and Corn Mint. The species is included in the Family Lamiaceae (the Mint Family), a major plant family world-wide. It includes many plants known to gardeners: the true mints, Wood mints, Savories, Lavenders, Hyssops and Sages. Most Family members are herbaceous plants or shrubs, and many have aromatic foliage. Many important cooking herbs are members of this family. [2]

Wild Mint (Mentha arvensis): can be used fresh or dried

Mentha arvensis is one of the culinary herbs, in addition to being a native plant. It has a wonderful, ‘true-mint’ aroma (think ‘mint extract’) and can be used, fresh or dry, as a cooking herb, seasoning and tea. In fact, oils of this plant are used to flavor candy, other edibles and toothpaste. It’s one of those plants that cooks should include in their gardens. Leaves can be harvested through summer, up to the first frost or so. For more on making mint tea, see: http://mother-natures-backyard.blogspot.com/2012/06/making-tea-from-california-native-mint.html.

Wild Mint (Mentha arvensis): spreading

herbaceous perennial

Mentha arvensis is a hardy, herbaceous perennial. It grows 1-2 ft. tall (to 0.5 m.) and spreads to 3-4 ft wide. Like many mints, it spreads by rhizomes, which are underground stems. This makes it useful as a filler plant under trees and shrubs. If space is limited – or if you want to limit the spread – you’ll need to contain it. Some gardeners even grow it in a container, rather than planting it in the ground. You can also plant it in a container buried in the ground (or covered with mulch).

Wild Mint (Mentha arvensis): foliage

Wild mint has square, herbaceous stems that are upright or sprawling. The square stems are a characteristic of the Mint Family. The stems are green, sometimes with some red or purple in sunnier locations. The stem may be hairy or smooth. The leaves are simple, green, opposite and may be smooth or hairy. The leaves are oval to oblong, 1 to 2 ½ inches long, with prominent veins and serrated edges. In short, the foliage looks like what we expect for a mint.

The flowers of Mentha arvensis are tiny – about 1/8 inch long. They range in color from white through pale pink or lavender. The flowers grow in clusters located in the axils of the upper leaves (where leaf meet stem). The flowers are not particularly showy, and may be almost hidden by the leaves. The flowers have no noticeable fragrance.

A closer view of the flowers reveals many characteristics typical of the Mints. The flowers are tubular, with petals divided into three upper lobes and a lower ‘lip’, which may also be divided. The flowers attract small native bees, small butterflies and hummingbirds. Additional pollinators include wasps and pollinator flies.

Wild Mint (Mentha arvensis): developing

capsules (fruits)

Wild mint blooms during the warm months. It can commence blooming as early as May in warmer climates (more often July in Colorado) and continues until October. The fruits are round and slightly fleshy with four nutlets. Fruits ripen from summer to fall. Fruits of Mints are toxic and should not be eaten. Take precautions if you have small children who pop such things in their mouth.

Wild Mint (Mentha arvensis): easily propagated

from cuttings

Wild mint is easy to grow, either from seed or cuttings. In Colorado, seed is best sown in fall (or give seeds a 2-3 month cold-moist stratification). Mints are known to hybridize easily, so seeds may not breed true. Cuttings are a more reliable source of plants with known characteristics. Stem or root cuttings can be made in spring or fall, with root cuttings being slightly easier (at least in our hands). Use a light growing medium and keep it moist. In warm weather, cuttings will root well in 2-4 weeks.

Wild mint is an easy-care garden perennial. It’s hardy from USDA Zones 4-10, and can be successfully grown even in warm Southern California. In all climates, it dies back to the roots in winter (or with successive frosts). It then sends up new stems with warm weather of spring.

Wild Mint (Mentha arvensis): new

stems emerge in spring

Mentha arvensis is not fussy about soil. It succeeds in clay to sandy soils, with a pH range of 6.5 to 8.0. If you’ve got really alkali soils (much above 8) you’d do better growing this plant in a container. Wild mint likes full sun to light shade; in a really hot garden, try placing it where it gets some afternoon shade. It does need regular water, preferring moist to semi-moist soils. In a good loam with leaf mulch, you can likely get away with giving it a good watering 1-2 times a week in summer.

Mints are susceptible to the usual array of insects that prey on young growth: whiteflies, spider mites, aphids and thrips. Watch for these and blast them off with water if you can. Since leaves are edibles, you’ll want to limit use of pesticides to Safer’s Soap – and then only if really needed. In our experience, mint patches in the ground are rarely seriously affected by these sucking insects. Rabbits, deer and other herbivores are usually deterred by the aroma.

Wild Mint (Mentha arvensis): in mint bed

Mother Nature's Montrose Garden

Wild mint makes a wonderful addition to the herb or vegetable garden. In addition to being edible, the mint aroma deters some common garden insect pests. Mints are often promoted as companion plants for tomatoes and brassicas. We like it as a perennial groundcover under trees or large shrubs. In Mother Nature’s Montrose Garden, we’ve started a mints bed under a row of Mock Orange and related shrubs.

If you grow medicinal plants, you’ll want to consider Mentha arvensis. The mints have long been used for their antiseptic properties and ability to settle an upset stomach. Wild Mint tea has traditionally been used in the treatment of fevers, headaches, digestive disorders and various minor ailments.[4] The tea should not be used by pregnant women – and should be used in moderation by all.

In summary, Wild Mint is a delightful native perennial with a long history or culinary and medicinal use. If you like to cook, make potpourri - or even make a natural pest repellant - you should consider this plant for your garden. At the very least, a pot of wild mint adds a delightfully fragrant note to summer afternoons!