Lemon balm, a calming herb, is a member of the mint family and shares a few of its characteristics, namely, a slightly minty aroma, similarly shaped leaves, and a propensity for rapid growth. With its lovely scent and flavor, lemon balm (also known as sweet balm or Melissa), can season dishes, flavor salads and tea, even freshen up a room in a vase of flowers. Another reason to love this perennial? It repels flies and mosquitoes.
climate-smart variety: herb
Includes citronella, which is lemon balm bred to have a high citronella oil content.
WHERE LEMON BALM THRIVES
Optimal type of soil
Plant it in well-drained, rich soil. The best way to achieve this is to add organic matter to the soil by mulching and composting. Make sure not to trample or in any way pack the soil around the plant to keep it aerated and well-drained.
Optimal shade & sun
Lemon balm should be planted in a spot that is mostly sunny but still gets some shade during the day.
While it prefers moist conditions, lemon balm is resistant to drought.
Lemon balm is a hardy plant and can be planted almost anywhere in the United States. The only places it won’t do well is where temperatures dip below 30 degrees, some winters in northern Maine, Minnesota, North Dakota, and Montana can kill lemon balm.
Adaptability to climate extremes
Lemon balm is resistant to climate extremes. It can be planted in a pot to move indoors during the winter if necessary. In very hot areas, lemon balm should be planted in places that receive some shade.
You can grow this perennial from seed. Lemon balm seeds need light to germinate, gently pat seeds into the soil and keep moist until they sprout. Or start with a cutting of a lemon balm plant. Plant your seeds or cuttings 18 to 20 inches apart in moist soil. Lemon balm grows very easily. To prevent a too-rapid spread of this robust plant, cut its flowers before they go to seed and weed out new plants each spring.
Best time of year to plant
Plant during the spring or summer in moist soil. Seeds can also be started indoors 6-8 weeks before your last frost and transplanted outside once they have at least 4 true leaves.
Lemon balm’s strong aroma attracts bees and deters gnats and mosquitoes so it pairs well with almost any fruit, vegetable, or herb. Tomatoes, melon, onions, cauliflower, broccoli, and cabbage are all good options.
When plants are 3 to 4 inches tall and have leaves, they’re ready to harvest. Since an entire lemon balm plant can regrow in about a month’s time during warm weather, don’t be afraid to cut back on the plant when it gets bushy.
Lemon balm grows best in moist soil, so consistent, deep watering - down to its roots - is important to a happy plant. Lemon balm becomes bitter when stressed. Frequency will vary regionally.
To keep the leaves clean and the soil moist, apply two inches of mulch every spring. In colder climates where the winter temperature drops below 0 degrees, mulch lemon balm in the fall to help it overwinter.
Work compost into the soil to add organic matter, and add a thin layer of fertilizer every few weeks, as you see fit. In all likelihood, lemon balm will grow quickly regardless of fertilization. Plus, over-fertilizing reduces flavor. Less is more for this plant.
Weed until young plants are established to prevent them from getting shaded out.
No noteworthy pest vulnerabilities but aphids and spider mites can become a problem.
Mint rust, a fungus that generates small orange, yellow, or brown pustules on the undersides of lemon balm leaves, can be fought using a heat treatment in which the roots are immersed in hot water, cooled, and then replanted. To prevent mint rust in the first place, keep plants thinned for adequate air circulation within the plant, and remove dead stems.
Septoria Leaf Spot, a fungus that occurs in rainy climates, creates leaf loss for lemon balm plants. You can identify leaf spot by the circular spots with dark centers that appear on older leaves of plants. Remove infected leaves but avoid handling infected plants when they are wet to minimize the spread of the fungus.
Verticillium Wilt is a soil borne fungus that causes plants to wilt without warning. Infected leaves will begin to curl and quickly turn yellow and fall. If you notice verticillium wilt in your garden remove infected plants immediately and burn or dispose off the plant matter.
Particular growing challenges
Lemon balm is commonly planted in pots to limit its rapid growth. Another way to keep on top of it is to continually harvest and cut back the lemon balm plant. The small flower that lemon balm produces will create plants near the lemon balm.
Harvest as needed. As with most herbs, the youngest leaves have the most flavor. The plant is at its maximum flavor right before it flowers in summer. You’ll know it’s preparing to flower when its lower leaves begin to yellow. If you harvest with roots and put it in water, the herb will stay fresh for up to a week.
For best storage, wrap lemon balm leaves in a moistened paper towel and place in an unsealed plastic bag for a few days.
Lemon balm can be dried in a dark, warm place.