The Mountain Laurel

One of the beautiful cool climate plants, Kalmia latifolia, which its very attractive pink flowers will grow well in a range of climates.

The trick to growing these free flowering plants is to give them enough sun to promote good flowering, and enough shade to protect them from the heat of summer.

This is not difficult to achieve, Kalmias will grow well in morning sun and afternoon shade, and are suited to growing near the drip line on the afternoon shaded side of a deciduous tree.

Glossy green foliage year round is topped off be the starry flowers in spring. When in full flower this is a most attractive plant, the bush is covered with flowers, and the ground beneath is a carpet of petals.

How To Grow Kalmia latifolia – Basic Care

Like many acid-loving plants, Kalmia prefers well-drained, moist, and slightly acidic soil. These growing conditions make it a natural companion for Camellias and Rhododendrons.

Best Position: Light and Shade Balance

Getting the light conditions right is key to healthy growth and abundant flowering.

• Morning sun and afternoon shade offer the perfect balance.
• Ideal placement: near the drip line on the shaded side of a deciduous tree — enough light for flowers, enough shade for protection from harsh summer heat.
• Avoid full, hot afternoon sun, which can scorch foliage and limit blooms.

Planting and Soil Preparation

• Prepare the soil: Loosen deeply and mix in well-rotted compost and aged cow manure.
• Ensure good drainage: The soil should hold moisture without becoming soggy.
• Plant carefully: Water in with a liquid seaweed fertiliser to promote root growth.
• Mulch well: Maintain a cool root zone using leaf litter, pine bark, or similar organic mulch.

Feeding and Watering

• Use a Camellia and Rhododendron fertiliser in spring.
• Keep soil moist, especially during the first two summers.

You will find that once established, Kalmia or ‘Mountain Laurel’ are an easy care plant. In good condition they will require little extra water except in very dry hot summers.

Popular Kalmia Varieties

Several cultivars are available, offering different flower colors and plant sizes to suit every garden

• K. angustifolia ‘Nana’ – A smaller growing variety.
• K. latifolia ‘Bulls Eye’ – Deeper Pink to Crimson Purple banded flowers
• K. latifolia ‘Carousel’  – Flowers are banded pink and white
• K. latifolia ‘Elf’ – A smaller growing variety
• K. latifolia ‘Ostbo Red’ – Red flowers as the name suggests.
• K. latifolia (Mountain Laurel) – Very attractive pink flowers.
• K. latifolia Clementine Churchill – Rosy pink flowers

Top 4 Tips for Success

• Avoid alkaline soils – they can cause leaf yellowing.
• Prune lightly after flowering to shape the bush and encourage new growth.
• Plant companions: Combine with Azaleas, Hydrangeas, or Ferns for an attractive woodland effect.
• Protect from strong winds, which can damage new growth and buds.

Propagating Kalmia latifolia by Air Layering

Kalmia latifolia, can be difficult to propagate from ordinary stem cuttings. It is a woody, slow-growing shrub and can be slow to produce roots.

For this reason, air layering is a useful method for propagating Kalmia latifolia. The branch remains attached to the parent plant while new roots develop, so it continues to receive water and nutrients during the rooting process.

Air layering takes a little more time and care than taking a cutting, but it is well suited to plants such as Kalmia that can be slow to root.

When to Air Layer Kalmia latifolia

The best time to air layer Kalmia latifolia is in spring or early summer, when the plant is actively growing.

Choose a healthy branch with firm, mature wood. A straight branch about pencil-thick to slightly finger-thick, approximately 6–15 mm in diameter, is ideal.

Avoid very thin, soft green growth, as it can easily snap when wounded.

Propagation

How to Air Layer Kalmia latifolia

1. Select a suitable branch

Choose a healthy, straight branch with firm, mature wood.

Clear away leaves and small side shoots from a section of about 15 cm (6 inches) around the point where you will make the air layer.

2. Remove a ring of bark

Use a sharp, clean knife to make two parallel cuts around the stem, about 1–1½ inches (2.5–4 cm) apart.

Make a vertical cut between the two rings and carefully peel away the strip of bark.

This leaves a ring of exposed wood.

3. Scrape away the cambium

Under the bark is the slippery, greenish cambium layer.

Gently scrape this layer away with the knife until you reach the dull, hard wood underneath.

This prevents the wound from simply healing over. Take care not to cut deeply into the wood or weaken the branch.

4. Apply rooting hormone

Apply a good-quality rooting hormone  to the upper part of the wound, where the new roots will develop.

5. Pack with damp sphagnum moss

Soak sphagnum moss in water, then squeeze it firmly so it is damp but not dripping wet.

Pack the moss around the wounded section, making sure the entire wound is covered and the moss is in close contact with the exposed wood.

6. Wrap the air layer

Wrap the moss firmly with clear plastic wrap.

Seal both ends securely with electrical tape or similar material so the moisture is retained.

7. Cover with foil

Cover the clear plastic with aluminium foil.

This keeps the developing roots in darkness and helps protect the air layer from direct sunlight and excessive heat.

8. Wait for the roots to develop

Kalmia latifolia is a slow-rooting plant, so this is the stage where patience is needed.

Allow 4–6 months for a useful root system to develop, checking occasionally to make sure the moss remains damp.

Do not cut the branch from the parent plant until you can see a good network of roots filling the moss ball.

9. Cut and pot the new plant

Once the roots are well developed, cut the branch below the rooted section.

Carefully remove the plastic without disturbing the roots and pot the new plant into a suitable acidic, well-drained potting mix.

Keep the newly rooted Kalmia well watered and protected while it becomes established.

Tips for Successful Air Layering

• Choose firm, mature wood rather than soft new growth.
• Use a sharp, clean knife when making the wound.
• Make sure the cambium is removed from the exposed section.
• Keep the sphagnum moss damp, but not waterlogged.
• Use rooting hormone containing IBA to encourage root formation.
• Keep the air layer shaded and protected from excessive heat.
• Most importantly, don’t rush the process. Wait for a good root system before separating the new plant.

Ground layering vs air layering

1. Ground layering — easiest where suitable branches are available
2. Air layering — useful for higher or less flexible branches

Propagating Kalmia latifolia by Ground Layering

Ground layering is another simple way to propagate Kalmia latifolia, provided you have a low-growing, flexible branch that can be brought down to the soil.

As with air layering, the advantage is that the new plant remains attached to the parent plant while roots develop. This makes it a useful method for Kalmia, which can be slow and difficult to root from ordinary cuttings.

How to Ground Layer Kalmia latifolia

1. Choose a suitable branch

Select a healthy, flexible branch that is growing low enough to reach the ground.

Spring or early summer, when the plant is actively growing, is a good time to start.

2. Prepare the soil

Choose a spot beneath the branch where the soil is moist, well drained and slightly acidic.

Loosen the soil to a depth of several centimetres where the branch will be buried.

3. Wound the branch

At the point where the branch will touch the soil, make a small cut or carefully remove a thin section of bark from the underside of the branch.

The aim is to create a wound that will encourage roots to form.

Apply a little rooting hormone containing IBA to the wounded section if desired.

4. Bury the wounded section

Make a shallow trench and place the wounded section of branch into it.

Cover the wound with soil, leaving the growing tip of the branch above the soil.

5. Secure the branch

Hold the buried section firmly in place with a U-shaped pin, wire peg or suitable rock.

Make sure the wounded section remains in close contact with the soil.

6. Keep it moist

Keep the soil around the layered branch evenly moist, particularly during dry periods.

Avoid waterlogging, as the buried section still needs good air circulation around the developing roots.

7. Wait for roots to develop

Kalmia is slow growing, so allow plenty of time for roots to form.

Rooting can take 6–12 months.

Leave the branch attached to the parent plant until a good root system has developed.

8. Separate the new plant

Once the new roots are well established, cut the rooted branch from the parent plant.

Carefully dig up the new plant, keeping as much of the root system and surrounding soil intact as possible, and transplant it into a suitable acidic, well-drained soil.

Keep the new plant well watered while it becomes established.

Find Kalmia latifolia at these nurseries .

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