How to Grow Lemon Balms USA

Growth Stages

Stage	BBCH	Notes
Planting	0	Plant in spring (RHS; USU gives around March specifically), spaced 18in apart, or in a container at least 25cm (10in) wide and deep with peat-free soil-based compost (RHS).
Establishment and spread control	3	Vigorous and mint-like in its tendency to spread and become weedy (RHS; USU). Container growing controls this most reliably; grown in the ground, USU recommends regular harvesting, removing flowers before they set seed, and digging around the plant's edges to check runners. Self-seeds unless deadheaded (RHS).
Harvest	8	RHS: pick the youngest leaves whenever needed through spring and summer, used fresh where possible. USU: harvest about a third of the foliage at monthly intervals before the plant blooms.
Propagation	0	RHS: divide clumps every few years, take softwood cuttings in spring/early summer, or allow self-seeding; named varieties should be propagated vegetatively. USU adds layering as a reliable method -- stake a flexible 6-12in stem under 2-3in of soil, roots form in 1-2 months -- and gives division specifics: root pieces with 3-4 buds, done in late August/September.

Quick Facts

Factor	Value
Drainage	Rich, humus-filled, moist, well-drained; avoid waterlogged sites (RHS; USU).
Lifecycle	Vigorous, clump-forming perennial herb in the mint family, lemon-scented. Both sources independently compare it to mint for its tendency to spread and become weedy -- RHS: "a tendency to spread" and "can take time to remove completely if you no longer want it"; USU: "like mint spreads rapidly (becomes weedy) and can take over an herb bed." Self-seeds unless deadheaded (RHS); USU adds that removing flowers before seed-set is one of the specific controls for in-ground spreading.
Edible parts	leaves

At a Glance

Harvest & Storage

When to pick: RHS: pick leaves whenever needed spring-summer, selecting the youngest for the best flavour; regrowth is quick so harvesting can be regular. USU: harvest about a third of the foliage at monthly intervals, before the plant blooms.

Storage

Use fresh where possible -- RHS notes fresh leaves have better flavour than dried. USU: to dry, tie stems into bundles and hang indoors away from direct sunlight.

Diseases

Powdery mildew

low

Named independently by both RHS and USU ("powdery mildew"), with RHS adding that cutting back affected stems stimulates fresh new growth.

Foot and root rot (general)

low

Named independently by both sources from slightly different angles -- RHS attributes it to cold, soggy winter conditions, USU to over-watering; both point to the same underlying excess-moisture cause.

Pests

Glasshouse red spider mite (two-spotted spider mite)

low

Tetranychus urticae

USU reports "mite" issues without a specific species -- recorded against the existing generic mite entity.

Leafhoppers

low

Cicadellidae (various spp.)

Named directly by RHS.

Aphids

low

Aphididae (various spp.)

Named directly by USU.

What university and government growers’ guides add about lemon balm

Four US university extension services describe the same plant. They agree on the basics and disagree on one point worth knowing about before you plant it.

• A hardy perennial in the mint family, listed for USDA zones 3a to 9b. (Wisconsin Extension)
• It grows in full sun to partial shade in moist, well-drained, fertile soil; once established it tolerates poor soil and drought. (Illinois Extension, Wisconsin Extension, Utah State Extension, NC State Extension)
• Plants are spaced 16 to 18 inches (about 40 to 45 cm) apart. (Wisconsin Extension, Utah State Extension)
• It is easy to propagate from seed, division or stem cuttings, and Utah State calls layering a more reliable method than seed. (Illinois Extension, Utah State Extension)
• Cut stems as needed, preferably before it flowers; regular harvesting helps contain its growth. (Illinois Extension, Utah State Extension)
• Spread is the thing to manage. Illinois says it spreads by setting a lot of seed and advises pruning flowering stalks before seed forms, while NC State says it self-seeds and spreads aggressively by rhizomes and suggests growing it in a container. Illinois adds that the cultivar ‘Compacta’ is sterile and does not set viable seed. (Illinois Extension, NC State Extension)
• Clumps generally decline after three to four seasons, so divide or replace them. (Wisconsin Extension)
• The nectar-rich flowers attract bees, butterflies and other pollinators. (NC State Extension)

Lemon balm in the USA: climate data

Lemon balm is listed for USDA zones 3a–9b (Wisconsin Extension). Of the 26 cities in the NOAA normals we use, 20 fall inside that range; Los Angeles, CA (10b), Miami, FL (11a), Orlando, FL (10a), Phoenix Sky Harbor, AZ (10a), San Diego Lindbergh Fld, CA (11a), Tampa, FL (10a) are warmer than the highest zone listed.

Dates are the median 32°F freeze dates and freeze-free days from NOAA NCEI U.S. Climate Normals 1991–2020; zones come from the USDA 2023 Plant Hardiness Zone Map (ZIP code of each city centre).

Sources for this section

• University of Wisconsin–Madison Division of Extension: Lemon Balm, Melissa officinalis
• University of Illinois Extension: Lemon Balm
• Utah State University Extension: How to Grow Lemon Balm in Your Garden
• NC State Extension: Melissa officinalis (Plant Toolbox)

Section researched and checked on 24 October 2026 by the SoilCommander Editorial Team. How we check facts: editorial policy.

Sources

1. Utah State University Extension - How to Grow Lemon Balm in Your Garden

   Site/soil: rich, humus-filled, moist, well-drained; grows in most soil types. Full sun preferred but tolerates partial shade, which produces larger, more succulent foliage. Spacing: 18in apart, planted early spring (around March); mature height 2-3ft. Propagation: seed (small, needs fine soil coverage); layering (6-12in flexible stem staked under 2-3in soil, roots in 1-2 months); division (root pieces with 3-4 buds, done late August/September). Harvest: about one-third of the foliage at monthly intervals, before blooming; tie stems in bundles and hang indoors away from direct sunlight to dry. Spreading: like mint, spreads rapidly and can take over an herb bed; container growing controls it, or in-ground: regular harvesting, removing flowers before seed-set, digging around plant edges. Pests/diseases: powdery mildew and root rots if over-watered; aphid and mite issues reported, though the herb's high natural oil concentration typically provides some protection.

These source is specific to this region. The full list of 2 sources behind this guide (Royal Horticultural Society, Utah State University Extension) is in the references of our UK guide to lemon balm; they describe the plant itself, which is the same wherever it grows.