Fertilising guide

How to fertilise Wisley Gaultheria (Gaultheria × wisleyensis)— schedule & NPK

Also called Wisley gaultheria, Wisley prickly heath, Gaulnettya.

More about wisley gaultheria

About Wisley Gaultheria

Gaultheria × wisleyensis · also called Wisley gaultheria, Wisley prickly heath · flowering

A hybrid evergreen Ericaceae shrub raised at RHS Wisley, bearing small bell-shaped white or pink flowers in late spring followed by long-lasting purple-red berries. It thrives in moist, acidic, peaty soils in partial shade and forms a dense mound, making it an excellent year-round border or ground-cover plant for woodland gardens.

Growth habit: Spreading, suckering evergreen shrub forming a dense mound or low thicket

What fertiliser wisley gaultheria actually wants — and why

Wisley Gaultheria 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 wisley gaultheria: 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 wisley gaultheria, 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 wisley gaultheria:

Apply an ericaceous (acidic) slow-release fertiliser in early spring. Avoid high-nitrogen or general-purpose feeds that raise soil pH. A second light feed after flowering supports berry development. 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 wisley gaultheria 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 wisley gaultheria

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

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

Signs you are over-feeding wisley gaultheria

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

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 wisley gaultheria

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 wisley gaultheria care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

Flush wisley gaultheria 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 wisley gaultheria

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 wisley gaultheria — frequently asked questions

What fertiliser does wisley gaultheria 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. Wisley Gaultheria 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 wisley gaultheria?

Apply an ericaceous (acidic) slow-release fertiliser in early spring. Avoid high-nitrogen or general-purpose feeds that raise soil pH. A second light feed after flowering supports berry development. Apply an ericaceous (acidic) slow-release fertiliser in early spring. Avoid high-nitrogen or general-purpose feeds that raise soil pH. A second light feed after flowering supports berry development. 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 wisley gaultheria?

What does over-feeding wisley gaultheria 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 wisley gaultheria 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 wisley gaultheria?