How to Grow Spearmint

The Helpful Herb That Can Become an Aromatic Pest

Close up of the flowers of the spearmint plant.

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If you had to tell the difference between spearmint, peppermint, and apple mint, could you? They are all beautifully scented, useful herbs from the genus Mentha that can make terrific additions to a garden. Though there are over 600 varieties or cultivars of mint, spearmint, deserves a closer look as to why you might need to give this hardy perennial a spot in your garden. 

Spearmint gets its name from its leaves, which compared to other mints are, as you guessed it, spear-shaped. Its botanical name is also taken from its pointy foliage -- Mentha Spicata means “spike bearing” mint. It is in these delicious pointy leaves that the magic happens. 

The chemical that affects flavor and aroma in most mint plants is menthol, but spearmint actually has a minimal amount of this compound compared to other species and varieties. What sets spearmint apart is a chemical called carvone. This same chemical is found in aromatic favorites like dill and caraway, and it results in a spicier smell and taste. Combined with the other compounds in spearmint, it gives the herb a spicy, citrus, mint taste that this herb is prized for.

Spearmint has been prized for a long time. The herb has been cultivated for culinary and medicinal purposes since the 1st century CE. It was mentioned in the bible as being so valuable, that, along with other spices, it was used to pay taxes.

From the Middle East, it moved to Britain by way of Roman soldiers, where it enjoyed much success in monastic and then cottage gardens as it spread. In the 14th century a person most likely under a penname, John Gardiner, writes about spearmint in Feate of Gardening, the earliest known work on horticulture in the English Language.  At the same time, it was a common ingredient in early kinds of toothpaste.

By the 15th century it was known to help with stomach ailments, a use it is still known for today. In today’s world, it may not be monetarily valuable, but it is just as useful. From being used in cocktails, teas, mint jelly, and non-traditional medicines, to candles and oils, the plant’s use has spread as much as it does in the garden. 

Botanical Name  Spearmint
Common Name  Mentha spicata
Plant Type   Herbaceous Perennial
Mature Size  18-36 inches
Sun Exposure  Full Sun- Part Shade
Soil Type  Well-draining, rich, moist soil
Soil pH  Neutral
Bloom Time  Summer
Flower Color  Lavender
Hardiness Zones  Zones 4 - 10, USA
Native Area   Europe and Asia
Toxicity  Non-toxic

Spearmint Care

Growing spearmint is not hard. In fact, sooner or later, if you plant your spearmint in the wrong place you will ask yourself how do I stop the mint from growing? The most important thing to consider when planting most types of mint is placing it somewhere that it does not encroach on other plants in your landscape.

Mint spreads by rhizomes and stolon. This growth makes the plant an excellent candidate for a container garden, but if you choose to plant in a bed or in the ground it should be spaced carefully allowing for spreading. Three feet apart is a good rule for spearmint which will allow time for your plant to mature to a sufficient height to harvest.

Harvesting is best done before the plant goes to flower as the flavor will be concentrated in the leaves. If you harvest consistently you can get numerous hauls of leaves throughout the season and can then dry your mint for use throughout the year. 

Light

Mints prefer full sun to partial shade. Spearmint can also be grown indoors under a grow light or on a bright windowsill.

Soil

Mints prefer a rich, moist, and well-drained soil. If potting, use a rich organic soilless mix.

Water

Water regularly, being careful not to overwater. Allow soil to go almost dry between watering, then soak thoroughly.

Temperature and Humidity

Spearmint thrives in USDA zones 4a to 11 and does not tolerate the cold. It does well indoors on a window or under a grow light.

Fertilizer

No need to fertilize, spearmint grows well on its own. But adding some additional nutrients post-harvest will rejuvenate for another haul.

Is Spearmint Toxic?

Spearmint is non-toxic and has many culinary and medicinal uses. The carvone found in this herb is excellent at repelling mosquitos and other nuisances while still being a great pollinator.

Propagating Spearmint

Plants and seeds are both are readily available and equally easy to grow. Of course, seeds do take more effort, but they are more cost-efficient.

Mint also grows easily from cuttings taken in the early spring using rooting hormone.

Growing Spearmint from Seeds

If you choose to start from seed start the process indoors eight to ten weeks before the last frost. Indoors, seeds will germinate in about two weeks. Keep the soil moist till there is germination and then mist daily, but take care not to saturate the soil. Having a fan next to your seedlings is a good idea to strengthen them. You can also sow directly outdoors in partially shaded, moist soil.

Identifying Spearmint

With care, spearmint can be distinguished from its close relatives. Apple mint, Mentha suaveolens, is easy to identify. It has softly rounded leaves, and its stems and leaves are covered in fine fluffy hairs called trichomes. The flowers of Apple mint are white or light pink, and the taste is less minty and almost fruity. 

Chocolate mint, Mentha x piperita ‘Chocolate’, has dark green leaves, is very fast growing and has rich reddish-brown stems. The smell and flavor are reminiscent of mint chocolate liqueur.

Lavender Mint, Mentha x piperita 'Lavender', is as ornamental as it is aromatic. This beauty has large purple blooms and can reach heights to 36 inches. There is also a tricky version of spearmint known as curly-leaf mint, Mentha spicata 'crispa'. This tall growing mint has all the traits of spearmint but with tightly curled leaves.