Do Freezing Temps Kill Lemon Balm?

Frost

• Light frost typically kills lemon balm's outer leaves, leaving them limp and blackened. Removing the affected leaves generally revives the plant until a heavy frost occurs. Heavy frost kills lemon balm's foliage, but it does not harm the plant's roots. The lemon balm will return the following spring with new foliage.

Freeze Protection

• Laying a 3- to 4-inch layer of straw or leaf-mold mulch around your lemon balm before winter arrives offers it protection from the effects of freezing and thawing during winter. Mulching is especially important in lemon balm's coldest hardiness zones, USDA zones 4 and 5. The mulch helps to ensure the roots are not damaged.

Frost Damage Prevention

• Covering your lemon balm with plant protectors in spring and/or fall when frost is expected can extend the plant's growing season. Although lemon balm typically begins growing in spring when the weather warms, a nursery-grown plant may be susceptible to late-spring frosts. Covering the plant before each night and removing the covering during each day until the danger of frost passes protects the plant from frost damage. Covering the lemon balm in fall when the first frosts are predicted may extend its growing season by several weeks; in many locations several weeks of frost-free weather occur between fall's first frost and a hard freeze.

Considerations

• Growing lemon balm in a container allows you to move it easily to a sheltered location when a frost or freeze is forecast. It also allows you to move the plant easily to a cool workshop, garage or basement to overwinter, eliminating concerns about whether or not the lemon balm will survive winter. Because lemon balm may not overwinter reliably in USDA zone 4 and cannot overwinter in USDA zones 1, 2 or 3, overwintering the plant indoors is a practical alternative to starting a new lemon balm plant every year.