Lemon balm, also known as common balm, is a truly rewarding and versatile plant that even novice gardeners can cultivate without much difficulty. This perennial herb, a member of the mint family, is known for its characteristic, refreshing lemon-scented leaves, which are popularly used in the kitchen, medicine, and aromatherapy alike. It is worth knowing that lemon balm has a vigorous growth habit and is prone to spreading, so this characteristic must be taken into account when choosing a planting location to avoid future annoyances. With proper care, it will reward us with an abundant harvest for years, enriching our food and drinks with its fresh leaves.
Lemon balm tolerates a wide range of soil types, but it thrives best in well-draining soil rich in organic matter. If the soil in your garden is clayey and compacted, it is worthwhile to improve its structure and drainage with compost or well-rotted manure. For overly sandy soils, incorporating organic matter helps to retain moisture and nutrients. It is not particularly sensitive to soil pH, but it prefers a slightly acidic to neutral medium, with a pH value between 6.0 and 7.5. Although the plant is extremely adaptable, careful soil preparation will be rewarded in the form of lusher, more aromatic foliage.
In terms of its light and water requirements, lemon balm prefers a sunny or partially shaded location. It can tolerate full sun, but in hotter climates or during summer heatwaves, afternoon shade will protect the leaves from scorching and fading. The plant has moderate water needs; it appreciates regular, even watering, especially during drier periods. Although established clumps can survive short droughts, stagnant water and overwatering should be avoided as they can lead to root rot. Maintaining the ideal balance is key to healthy growth.
When choosing the right growing site, we must consider the spreading nature of lemon balm. It easily propagates by root runners and self-seeding, so it is advisable to plant it either in an area surrounded by a border or in a large pot or container. It can also serve as an excellent companion plant in the garden; it attracts pollinating insects, such as bees, while its scent repels certain pests. It pairs well with tomatoes, broccoli, cabbage, and most fruit trees, contributing to the garden’s biodiversity and plant protection.
Planting from seed and seedlings
Propagating lemon balm from seed is a cost-effective method that is best started indoors under controlled conditions. Sowing should be timed 6-8 weeks before the last spring frost, allowing the seedlings to become strong enough for transplanting. Since lemon balm seeds need light to germinate, do not cover them with a thick layer of soil; it is sufficient to press them lightly onto the surface of the seedling mix. The ideal temperature for germination is around 20°C (68°F), and it is important to keep the soil consistently moist. The seeds typically germinate in 7-14 days.
If you decide to sow directly, the seeds can be planted directly in the garden after the danger of spring frost has passed and the soil has warmed up. Before sowing, carefully prepare the bed, weed it, and loosen the soil. Here too, sow the seeds shallowly, almost on the soil surface, so they receive enough light for germination. Once the small plants reach a few centimeters in height and have their first true leaves, thin them to the appropriate spacing so they do not hinder each other’s development.
The easiest and quickest way to establish lemon balm is to purchase or plant out pre-grown seedlings. Before transplanting, the seedlings should be hardened off for a few days to acclimate them to outdoor conditions. This process involves placing the plants outside during the day for increasingly longer periods, while still protecting them from night frosts. When planting, place the seedlings at the same depth as they were in their original container, spacing them about 40-50 cm (16-20 inches) apart to give them enough room to grow. Thorough watering after planting is essential for proper root contact and establishment.
Growing lemon balm in containers is an excellent alternative, especially for those who want to control the plant’s spread or only have a balcony or patio for gardening. Choose a pot or container at least 30 cm (12 inches) in diameter with good drainage holes. Use a high-quality, nutrient-rich potting mix and remember that container-grown plants require more frequent watering and feeding than their counterparts planted in the ground. Potted lemon balm is also easier to protect from frost in winter by moving it to a sheltered location, such as an unheated garage or porch.
Vegetative propagation methods for lemon balm
The simplest and most commonly used vegetative method for propagating lemon balm is division. This method not only provides new plants but also serves to rejuvenate old clumps that have become too dense or bare in the center. The ideal time for division is in early spring when new shoots appear, or in autumn at the end of the growing season. To do this, carefully lift the entire plant from the ground with a spade or digging fork, then use a sharp knife or spade to divide the root ball into several viable sections. The divided clumps should then be immediately planted in their final location and watered thoroughly.
Taking cuttings is another effective procedure for creating genetically identical copies of a favorite lemon balm plant. The best time for taking cuttings is late spring or early summer when the plant is actively growing but has not yet started to flower. Select a healthy, strong shoot about 10-15 cm (4-6 inches) long and cut it from the plant with a sharp knife or pruning shears. Remove the lower leaves from the shoot, then place the cutting in a glass of water or a moist rooting medium, such as a mixture of perlite and peat. Roots usually appear within a few weeks, after which the young plantlet can be potted up.
A lesser-known but extremely simple method is layering, which mimics the plant’s natural spreading mechanism. For this, choose a long, flexible stem growing close to the ground. Carefully bend it down to the soil and, at the point where the stem touches the ground, make a small incision in the bark with a sharp knife. Pin this wounded section to the ground with a wire peg and cover it with a little soil, leaving the tip of the shoot exposed. Roots will eventually develop at the covered part, and once the new plant is established, it can be severed from the parent plant.
Lemon balm is prone to self-seeding, which is a natural form of propagation but can easily become invasive in the garden. If the plant is allowed to flower and set seed, you can expect a multitude of tiny lemon balm seedlings to appear around the parent plant the following spring. This phenomenon can be managed in two ways: either regularly cut off the spent flower heads before they produce seeds, or take advantage of the free seedlings. The volunteer seedlings can be carefully dug up and transplanted to other parts of the garden or given away to other gardening friends.
Care, harvesting, and managing common problems
Lemon balm is an extremely low-maintenance plant that requires little care after establishment. Fertilizing should be done sparingly; excessive nitrogen fertilizer may result in lush foliage but will reduce the essential oil content and aroma of the leaves. Working a thin layer of compost into the soil once a year in spring is more than sufficient for it. Mulching the soil surface helps to retain moisture, suppress weeds, and protect the roots in winter. It is worthwhile to cut the plant back hard periodically, especially after flowering, to encourage fresh, bushy growth.
Harvesting the leaves is best done in the morning hours, after the dew has dried but before the heat of the sun reduces the concentration of essential oils. Harvesting can be done by picking individual leaves or by cutting back the stems. Regular harvesting encourages the plant to produce new shoots, resulting in a bushier, fuller clump. The most intensely flavored and scented leaves can be collected just before flowering. The harvested leaves can be used fresh or preserved for the winter months by drying or freezing.
Fortunately, lemon balm is quite resistant to diseases and pests, primarily due to the essential oils contained in its leaves. The most common problem can be the appearance of powdery mildew, especially in humid, warm weather and in poorly ventilated locations. To prevent this, ensure adequate spacing for good air circulation and avoid wetting the foliage when watering. Occasionally, aphids or spider mites may also appear, but organic remedies, such as spraying with insecticidal soap, are usually effective against them.
As lemon balm is a perennial plant, it overwinters in temperate climates without any special protection. In colder regions, a thick layer of mulch (straw, leaves) spread around the base of the plants before winter can help protect the root system from severe frosts. The clumps of lemon balm can become old and woody in the center after a few years. To maintain the plant’s vigor and productivity, it is advisable to rejuvenate the clumps by division every 3-4 years. This process ensures that healthy and aromatic lemon balm grows in your garden year after year.
