How to Plant, Grow and Care For Lemon Balm

If you need a lowkey ornamental that dual-functions as a companion plant, lemon balm will be your new favorite garden herb. Also known as Melissa officinalis, this bushy perennial has an herbaceous lemony smell and beautiful purple or white flowers. It magnetizes pollinators and beneficial bugs while repelling the bad ones.

Lemon Balm benefits almost any vegetable in the garden, and also carries plenty of ornamental appeal. It thrives on neglect, although it can take over if not properly cared for.

Whether you need a fragrant pest-repellant or beautiful ornamental plant, this is a gorgeous perennial herb that you can plant once and enjoy for years to come. Let’s dig into everything you need to know about growing lemon balm!

About Lemon Balm

Lemon balm (Melissa officinalis) is a mint-family herb with fragrant, edible leaves and bee-magnetizing flowers. It is perennial in USDA zones 4 through 9, but its herbaceous nature means it dies back to the ground in the winter and regrows its stems each spring.

Like its minty cousins, lemon balm has the characteristic square stems, opposite leaves, and spike-shaped flowers of the Lamiaceae family.

Benefits of Lemon Balm in Your Garden

In the garden, Melissa officinalis is most commonly grown as a low-growing ornamental shrub and pollinator habitat. It can be planted in herb gardens, landscape border beds, or on the margins of vegetable gardens as a companion plant.

The ecological benefits in your garden include:

Native Regions

This zesty herb originated in North Africa and the Middle East and naturalized in Southern Europe as early as the 1500s.

When lemon balm arrived in America in 1700, the plant quickly naturalized and can now be found growing wild throughout the U.S. Like its mint cousin, it is not considered invasive, but it can “escape” gardens fairly easily under the right conditions.

Propagation

Melissa officinalis is vigorous and easy to propagate by seed, cutting, or division. If you have a friend with lemon balm, the easiest way to get started is to dig up a chunk of their plant. On the other hand, if you want a special variety (like the pretty gold-flecked ‘Aurea’), it’s best to start your patch from a nursery transplant.

Propagation by Seed

Melissa officinalis seeds should be sown in early spring around March or April. You can start indoors 6-8 weeks before the last frost or direct sow into the garden once temperatures are consistently above 50°F. This popular herb can be grown indoors but is commonly transplanted into outdoor gardens when plants mature.

These seeds are exceptionally tiny, so you should barely cover the seeds with a fine dusting of soil or sand. Sterilized potting mix is ideal.

While the seeds need moisture to germinate, you should keep watering to a minimum. Only water enough to prevent the seeds from drying out. Lightly pre-wet the potting mix before planting and then use a mister to spray the soil surface until germination.

Lemon balm takes 7-14 days to germinate and prefers soil temperatures between 65-70°F. If sowing in open flats, you can transplant to individual containers when the seedlings have two sets of true leaves. Generally, the plant takes about 70 days from the seeding date to reach maturity and begin flowering.

Propagation by Cuttings

During late spring and early summer, Melissa officinalis provides a practically endless supply of softwood cuttings. These tender pliable tips easily root into water or soil and grow into whole new plants within a month. 

To multiply a lemon balm plant very quickly:

1. Find a healthy, flexible stem on an established plant.
2. Ensure that the stem does not have any flowers on it.
3. Measure 4-6” from the vibrant green tip and cut the stem just below a node
4. Use sanitized garden shears or a sharp knife.
5. Strip the lower two-thirds of leaves from the stem.
6. Submerge the cutting into water or a well-drained soil blend.
7. Change the water or maintain consistently moist soil for 1-2 months.
8. When several strong roots have established, transplant the cutting.

Propagation by Division

Melissa officinalis plants have strong roots that can easily be divided into clumps in the spring or early fall. Division is also great for preventing lemon balm from spreading beyond its scope in the garden. You can re-plant divisions in a new location or pot them up and give them away.

To divide:

1. Be sure that the mother plant is thoroughly established (at least 2 feet wide and tall).
2. Division is best when the plant does not have any flowers on it.
3. Optionally, prune back the stems to 4-6” above the ground.
4. Use the top of a shovel or trowel to slice the root ball in half.
5. Then push the shovel into the soil 1-2” around the perimeter.
6. Leverage your shovel to lift the root clump from the soil and transplant the division.
7. Backfill the hole where you want the original plant to stay.

Propagation by Layering

Layering is a simple propagation technique that involves burying a long lemon balm stem in the soil to encourage the plant to spread outward. The new plant remains partially attached to the mother plant as it forms new roots along the buried stem.

If you have a planting that you’d like to expand, follow these simple steps to grow the patch:

1. Locate a low-growing stem that is established and flexible.
2. It should be at least 6-12” long.
3. Gently lay the stem laterally on the ground next to the mother plant.
4. Use a landscape staple to stake it in place.
5. Cover the entire stem with 2-3 inches of soil, leaving only the tip exposed above ground.
6. Keep the soil moist and notice roots forming in 1-2 months.
7. The stem may naturally decay off of the base of the mother plant.
8. Cut it back once it seems established.

Planting

The best time to plant Melissa officinalis is in the late spring when the weather is reliably warm and all chances of frost have passed. You can plant from homegrown seedlings, store bought starts, or large clump divisions.

Transplanting

Whether growing from seed, cutting, or a nursery start, you want to check your lemon balm’s roots before transplanting. The root ball should be strong and white, with the roots holding onto the surrounding soil. If the plant has become rootbound in its container, use your fingers to loosen the tightly bound areas.

To transplant:

1. First, choose a site where Melissa officinalis can live permanently.
2. Don’t plant in your annual vegetable beds.
3. Instead, opt for a margin bed or ornamental landscape bed.
4. Place it where the plant can get full sun to partial shade during the majority of the day.
5. Thoroughly aerate the soil and mix several shovel-fulls of aged compost into the upper few inches of soil.
6. Use a broadfork in heavy clay soils.
7. Optionally, mix in a small amount of all-purpose organic fertilizer for slow-release fertility.
8. Avoid over-fertilizing or using manure-rich compost.
9. Dig a hole that is twice the size of the root ball.
10. Hold the plant from the base of the stem and gently loosen it from the container.
11. Place the plant in the hole and backfill until the soil level is the same as it was originally.
12. Avoid burying the stems or leaves.
13. Thoroughly water the transplant and maintain consistent moisture for the next 2-3 weeks as it establishes.

Spacing

Space lemon balm plants 18-24” apart. If you are growing a dwarf variety, use closer spacing around 12-18” and prune regularly. For container plantings, plant in at least a half-gallon pot for the best results.

How to Grow Lemon Balm

Melissa officinalis is as easy to grow as mint, but it doesn’t need as much water nor does it spread as easily. If you get these simple conditions right at the time of planting, you won’t have to bother with your lemon balm unless you’re harvesting it!

Light

Melissa officinalis thrives in full sunshine to partial shade. In hot climates, you should plant in a place where it gets some shade during peak daylight. It does exceptionally well next to angelica, hollyhock, nasturtiums, geraniums, lavender, and asters.

Water

Lemon balm prefers soil that is moist but never wet. This drought-tolerant plant prefers to be on the dryer side, but can’t be quite as dry as herbs like rosemary and lavender. Allow the top 1-2 inches of soil to dry out before watering again. Ensure there is plenty of organic matter in the soil and mulch over the root zone to help retain moisture during hot summer days.

The Melissa plant needs the most water during establishment. You should check on newly planted Melissa officinalis every few days. Once the herb has anchored its root system into the soil, it only needs water once every week or so.

In climates with consistent summer rains, you probably won’t need to install irrigation lines near lemon balm. In dryer climates, it does best with a soaker hose or drip line near its base.

Soil

The best soil is rich in organic matter and drains freely. This plant is prone to root rot, so it’s especially important that you amend heavy clay soils with compost, peat moss, coco coir, or horticultural sand.

A pH between 6.5 and 7.0 is ideal, but the plant is not too finicky about acidity.

You only plant Melissa officinalis once, so it’s best to do proper soil preparation in advance. Broadforking or double-digging ensures that the roots can establish quickly and never sit in a pool of water.

For containers, most general potting soils work just fine. If the mix appears too dense or soggy, consider adding extra perlite or vermiculite to increase the drainage. You can also mix a standard potting soil with a cactus mix to keep Melissa officinalis happier in a pot.

Climate and Temperature

Lemon balm grows best in USDA zones 4 through 9. It is frost-hardy, perennial, and somewhat heat-tolerant. During the growing season, Melissa prefers a chill 50-85°F.

The plant can handle hotter temperatures as long as it has plenty of water and shade. Gardeners in hot southern climates should plant in the partial shade of taller perennial shrubs so it doesn’t get scorched by the sun.

During its dormant phase, this hardy perennial tolerates down to a frigid -20°F. Keep in mind that it may appear dead during cold winters because its above-ground parts die back. Rest assured that the roots are still alive and well beneath the soil surface. For added protection in harsh cold climates, deeply mulch with leaves or straw in the fall.

Fertilizing

The best way to fertilize lemon balm is by side dressing with compost or mulch in the spring and fall. Melissa officinalis likes a little dose of all-purpose organic fertilizer now and then, but it’s important not to over-fertilize.

Like most aromatic plants, excessive nitrogen can cause the plant to lose its delightful fragrance. Synthetic fertilizers are particularly problematic because they provide a quick dose of nitrates that can dramatically reduce the perfume of the herb.

Maintenance

Lemon balm doesn’t ask for much more than a haircut once or twice a year. In the spring, cut back the plant to about half its height. In the fall, you can prune all the way back to the ground and leave the mound to regenerate itself in the spring.

If you don’t prune this herbaceous perennial will die back when frosts arrive anyhow. Pruning in advance of cold weather will help the plant enter dormancy and prevent any diseases from overwintering on the fallen branches.

Varieties

The Melissa genus includes an array of varieties that have been bred for specific colors and scents. Fortunately, all of them are grown the same and can be interspersed throughout your garden for more diversity. My favorites include:

• Classic Lemon Balm: The wild-type M. officinalis is the most common and prolific variety of balm. It has vibrant green leaves that grow 1 to 3 feet tall and wide. It is an all-purpose cultivar suitable for all uses, including ornamental landscaping, culinary flavorings, herbal preparations, and companion planting.
• Variegated Lemon Balm: For a brilliant contrast of golden-yellow and green accents, this dwarf cultivar adds a spike of color and works great for container growing. It has an extra strong minty flavor and bright white flowers during the summer.
• ‘Aurea’ Lemon Balm: The crinkly oval-shaped leaves of this variety have golden flecks and clusters of pale cream-colored blooms.
• ‘Quedlinburger’ Lemon Balm: This variety has the highest amount of essential oils and the strongest smell for pest repellent properties.
• ‘Lime’ Lemon Balm: Lime balm (Melissa officinalis ssp. altissima) is closely related to Melissa officinalis but has a zestier scent reminiscent of limes. Its leaves are brighter green, but it is otherwise identical to lemon balm.

Pests and Diseases

The strong citronella-rich smell of lemon balm keeps most pests and pathogens at bay. However, you may notice a few of these problems on your plants. Thankfully, they have very simple

Aphids

No garden plant is completely immune to aphids. These sap-suckers may still appear on the undersides of your lemon balm leaves.

To get rid of them, apply a diluted neem solution or blast with water to remove aphids. You can also companion plants with calendula and marigolds to attract beneficial aphid predators.

Powdery Mildew

A fluffy white growth on your Melissa officinalis is a sign of powdery mildew. Too much congestion, shade, or moisture can cause this fungus to grow over your lemon balm. In extreme infections, powdery mildew prevents the plant from photosynthesizing properly.

To eliminate and prevent powdery mildew:

• Remove any infected plant parts and throw them in the trash.
• In humid climates, always plant in full sunlight. Shade promotes more mildew growth.
• Avoid overhead irrigation. When water sits on the leaves, it attracts fungal infections.
• Sanitize pruning tools regularly with diluted bleach solution.
• Apply a diluted neem solution to the leaves.
• Regularly thin out patches to prevent overcrowding.
• Prune to encourage aeration.

Septoria Leaf Spot

This seed-borne or debris-spread fungus is a major problem in commercial production, as well as tomatoes and other crops.

The infection looks like brownish-yellow spots on the leaves that quickly spread over the foliage. This is most problematic in rainy areas or gardens with overhead irrigation. Use the same prevention techniques as above and source certified disease-free seeds.

Frequently Asked Questions