Fertilising guide

How to fertilise Compact bog rosemary (Andromeda polifolia 'Compacta')— schedule & NPK

Also called Compact bog rosemary, Compacta bog rosemary.

More about compact bog rosemary

About Compact bog rosemary

Andromeda polifolia 'Compacta' · also called Compact bog rosemary, Compacta bog rosemary · flowering

Compact bog rosemary 'Compacta' is a dwarf cultivar of Andromeda polifolia forming a tight mound of narrow, blue-grey evergreen leaves. It bears clusters of rosy-pink urn-shaped flowers in spring. An excellent choice for small bog gardens, alpine troughs, and acidic rock gardens, it is fully hardy and very low maintenance.

Growth habit: Dwarf, dense, mound-forming evergreen subshrub

Watch for — Loss of compact habit: Excessive nitrogen fertiliser or deep shade causes the plant to grow loosely and lose its tight mounded form. Withhold extra feeding, move to a sunnier position, and trim lightly after flowering to encourage bushiness.

What fertiliser compact bog rosemary actually wants — and why

Compact bog rosemary 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.

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 compact bog rosemary: 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 compact bog rosemary, 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 compact bog rosemary:

The dormant-season rule matters more than the exact interval: skip feeding entirely when compact bog rosemary 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 compact bog rosemary

Follow the ericaceous product's own rate — these are formulated for the plant, so the dilution on the label is right for compact bog rosemary. The variable that actually matters is pH, not concentration.

Feeding always goes onto already-damp soil, never dry roots — water compact bog rosemary first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the compact bog rosemary watering schedule.

Signs you are over-feeding compact bog rosemary

Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for compact bog rosemary:

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 compact bog rosemary

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 compact bog rosemary care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

Flush compact bog rosemary 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 compact bog rosemary

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 compact bog rosemary — frequently asked questions

What fertiliser does compact bog rosemary 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. Compact bog rosemary 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 compact bog rosemary?

Apply a very dilute ericaceous liquid fertiliser once in early spring. This cultivar is adapted to extremely nutrient-poor bog conditions and does not require or benefit from regular feeding. Excess nutrients cause rapid, soft growth that breaks the compact form. Apply a very dilute ericaceous liquid fertiliser once in early spring. This cultivar is adapted to extremely nutrient-poor bog conditions and does not require or benefit from regular feeding. Excess nutrients cause rapid, soft growth that breaks the compact form. 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 compact bog rosemary?

What does over-feeding compact bog rosemary 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 compact bog rosemary 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 compact bog rosemary?