Of all the many varieties of Mint, peppermint [Mentha x piperita] is perhaps the most widely known and popular. It has its origins in 18th Century England and has been used ever since as a flavoring agent for multiple confections as well as herbal concoctions and pharmaceuticals. There are several sub varieties of peppermint which include Peppermint, Variegated Peppermint as well as black and white peppermint.
Perennial in zones 3 to 11. In other areas it is best grown as an annual or potted and transported indoors in Winter. Although Peppermint is a perennial, its quality wanes after 3 to 5 years and should be replaced.
Soil pH 6.0 to 7.0
Full Sun or Partial Shade. Full Sun will produce a higher concentration of oils and a more robust flavor. Partial shade will produce lush foliage with a weaker flavor and aroma.
Not Frost Tolerant
Not Drought Tolerant
Soil: Will grow in just about any soil that retains moisture, even clay type soils.
Space Seedlings 18 to 24 inches apart
Mature height: 1 to 3 feet. If left unharvested and not maintained they can grow into 4 foot monstrosities.
The leaves are saw toothed and commonly a vibrant green, although color varies slightly in some cultivars. Black peppermint has deeper greenish purple leaves and a higher concentration of essential oils. They are used fresh, dried, made into extracts or even frozen such as in Herbal Ice. It blooms in late summer with small and attractive pale purple flowers.
Starting Peppermint Plants
Peppermint is best started via root divisions, but starting from seed is feassible. Germination is relatively quick, in the two week vicinity. A drawback to starting from seed however is that Mint is notorious for hybridization, so there is no guarantee that the seed you plant will produce true, you could end up with an undesirable poor quality hybrid.
Root divisions, if you have access to a plant from which to take some work best. Any section of the root is a candidate to produce a new plant. Larger root divisions can be planted directly into the soil in the appropriate zones.
Peppermint is not drought tolerant, it requires persistent moisture. It is slightly frost tolerant but fades rapidly in temperature fluctuations. It will grow in full sun, in fact full sun will increase its vigor and flavor as the plant produces more of the oils which create the peppermint flavor. However if you live in a very hot region partial shade is advisable.
Mint varieties when grown close to one another have a tendency to cross pollinate. This end result is usually undesirable so it is advisable to keep various mint varieties a safe distance from one another.
A good companion plant for any Brassica plants such as Cabbage, cauliflower, kale, broccoli, Chinese cabbage. Will also work well as a border for garden areas prone to attack by deer and wild herbivores. Repels some insects such as cabbage moths, aphids ,flea beetles. Keep it away from Chamomile as this plant inhibits the mints ability to produce the essential oils that create the menthol flavor and aroma.
Mint is invasive and will spread prolifically if left unchecked. Keep the plants in check by harvesting the tips on a regular basis and removing renegade runners. Small flowers bloom from June to September, you should trim these before the buds open to keep the plant compact and manageable.
Another method of controlling mint plant is using bottomless containers 12 - 15 inches in depth and sunk in the ground with one or two inches protruding above the soil surface. Another is to plant them above ground in containers.
Fertilizer is not necessary so long as the soil is reasonably fertile. If your soil is abysmal Modest amounts of fertilizer can't hurt. Fertilize in early Spring and then every fifth week thereafter with a balanced fertilizer. No more than 3 X per season and in Modest amounts.
A layer of mulch in the Autumn will help protect them in their winter dormancy.