Lemon balm is a fresh-smelling hardy herb that grows well in many climates and soil conditions. Lemon balm grows best in direct sunlight but it will also grow well in a partly shady area. It is a plant that likes frequent watering, although a little neglect is unlikely to kill it. The three simple ways to propagate lemon balm are plant division, layering and from seed.
Dig up an old lemon balm plant in August or September. Use a garden fork or spade to get under the roots and free it from the soil.
Divide the plant by pulling off sections of the root pieces. Each section should contain three or four buds.
Plant each section in the ground 18 to 24 inches apart. Propagating in August and September is optimal for plant division because it allows the roots to establish before the first winter frost.
Water lemon balm plants thoroughly and often, keeping the ground moist around your new plants.
From your established lemon balm plant select flexible stems that are between 6 and 12 inches long.
Make a small slit in the underside of the flexible stem a few inches from the end.
Press the slit area of the stem into the ground, covered with 3 to 4 inches of soil.
In a month or two, the roots will have developed. At this point you can sever the stems from the original plant and transplant your newly rooted lemon balm plants into pots or into another area of the garden.
Prepare a garden bed by turning the soil with a fork and flattening with a rake or hoe.
In the spring, scatter lemon balm seeds liberally onto the garden bed.
Cover with an inch of soil to prevent the seeds from blowing away or being eaten by birds.
Water the area thoroughly and keep the area moist while the seeds are germinating and growing.