Fertilising guide
How to fertilise mountain laurel (Kalmia latifolia)— schedule & NPK
Also called mountain laurel, calico bush, spoonwood.
More about mountain laurel
About mountain laurel
Kalmia latifolia · also called mountain laurel, calico bush · flowering
Mountain laurel is a broadleaf evergreen shrub native to eastern North America, producing spectacular clusters of intricate, crimped-bud flowers in shades of white, pink, or red in late spring. A slow-growing woodland understory plant, it thrives in acidic, humus-rich soils and dappled shade, making it ideal alongside rhododendrons and azaleas.
Growth habit: Mounding, broadleaf evergreen shrub; dense and multi-stemmed
What fertiliser mountain laurel actually wants — and why
mountain laurel is an acid-loving plant — it can only take up nutrients in acidic soil, so the feed itself matters less than using an ericaceous formula and never liming.
An ericaceous (acidic) fertiliser, formulated to keep the soil pH low and supply iron and trace elements in a form acid-loving roots can absorb. Ordinary feeds and any lime lock out iron and yellow the leaves.
For the language behind the three numbers on the bottle — what nitrogen, phosphorus and potassium each do — see the NPK ratio explained entry. The short version for mountain laurel: match the feed to the job the plant is doing right now, not to a generic “plant food” on the shelf.
How often to feed mountain laurel, and which months
Feeding only earns its keep while the plant is in active growth and can use the nutrients — pour feed into a dormant or low-light plant and it simply builds up as root-burning salt. For mountain laurel:
Use an ericaceous (acid) slow-release fertiliser in spring. Feed sparingly — mountain laurel is not a heavy feeder and excess nitrogen reduces flowering. A mulch of composted pine needles or bark provides gentle nutrition. In practice: an ericaceous feed in spring as growth resumes, repeated through the main growing months; never apply lime, bonemeal or wood ash, which raise pH.
The dormant-season rule matters more than the exact interval: skip feeding entirely when mountain laurel is resting. For the wider context on indoor feeding rhythms across the seasons, the houseplant fertiliser schedule walks through the year month by month.
What strength to mix for mountain laurel
Follow the ericaceous product's own rate — these are formulated for the plant, so the dilution on the label is right for mountain laurel. The variable that actually matters is pH, not concentration.
Feeding always goes onto already-damp soil, never dry roots — water mountain laurel first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the mountain laurel watering schedule.
Signs you are over-feeding mountain laurel
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for mountain laurel:
- Brown, scorched leaf margins from too strong or too frequent a dose.
- White salt crust on the soil surface.
- Soft, lush growth that fruits or flowers poorly.
Signs you are under-feeding mountain laurel
- Yellowing leaves with green veins (iron chlorosis from high pH).
- Weak growth, poor cropping and an overall pale, stressed look.
- Stunted new shoots in spring despite adequate water and light.
If the symptoms point at watering, light or roots rather than nutrition, the full mountain laurel care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush mountain laurel with rainwater (not hard tap water, which raises pH) if salts build up; better still, mulch with pine needles or composted bark and water with rainwater to hold the acidity.
Organic vs synthetic feeds for mountain laurel
Organic options
Composted pine bark, pine-needle mulch, used coffee grounds and an organic ericaceous feed gently maintain acidity. UK: Vitax or Westland Ericaceous; US: Espoma Holly-tone or Dr. Earth Acid Lovers. Slow, soil-improving, hard to overdo.
Synthetic / liquid feeds
A liquid or granular ericaceous feed — UK: Miracle-Gro Ericaceous, Vitax or Westland; US: Miracle-Gro Acid-Loving Plant Food or Espoma Holly-tone. Pair with rainwater and an acidic mulch for it to work.
Brand names are examples, not endorsements, and UK and US ranges differ — check the label’s own NPK and dilution rate, since formulations change.
Fertilising mountain laurel — frequently asked questions
What fertiliser does mountain laurel need?
An ericaceous (acidic) fertiliser, formulated to keep the soil pH low and supply iron and trace elements in a form acid-loving roots can absorb. Ordinary feeds and any lime lock out iron and yellow the leaves. mountain laurel is an acid-loving plant — it can only take up nutrients in acidic soil, so the feed itself matters less than using an ericaceous formula and never liming.
How often should I feed mountain laurel?
Use an ericaceous (acid) slow-release fertiliser in spring. Feed sparingly — mountain laurel is not a heavy feeder and excess nitrogen reduces flowering. A mulch of composted pine needles or bark provides gentle nutrition. Use an ericaceous (acid) slow-release fertiliser in spring. Feed sparingly — mountain laurel is not a heavy feeder and excess nitrogen reduces flowering. A mulch of composted pine needles or bark provides gentle nutrition. In practice: an ericaceous feed in spring as growth resumes, repeated through the main growing months; never apply lime, bonemeal or wood ash, which raise pH.
What strength of feed for mountain laurel?
Follow the ericaceous product's own rate — these are formulated for the plant, so the dilution on the label is right for mountain laurel. The variable that actually matters is pH, not concentration.
What does over-feeding mountain laurel look like?
Brown, scorched leaf margins from too strong or too frequent a dose. White salt crust on the soil surface. Soft, lush growth that fruits or flowers poorly. Feeding mountain laurel an ordinary fertiliser, or growing it in hard tap water / limey soil, is the defining mistake — it triggers lime-induced chlorosis (yellow leaves, green veins) no amount of feeding fixes until the pH comes down.
Should I flush the soil of mountain laurel?
Flush mountain laurel with rainwater (not hard tap water, which raises pH) if salts build up; better still, mulch with pine needles or composted bark and water with rainwater to hold the acidity.
Keep reading
- mountain laurel care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water mountain laurel — the watering schedule
- The houseplant fertiliser schedule — feeding through the year
- NPK ratio explained — what the three numbers on the bottle mean
- How to fertilise nymphaea 'pygmaea rubra'
- How to fertilise nymphaea 'firecrest'
- How to fertilise nymphaea capensis
- All 6887 fertilising guides in the Growli library