Fertilising guide

How to fertilise Cascade Purple Aubrieta (Aubrieta 'Cascade Purple')— schedule & NPK

Also called Cascade Purple Aubrieta, Purple Rock Cress.

More about cascade purple aubrieta

About Cascade Purple Aubrieta

Aubrieta 'Cascade Purple' · also called Cascade Purple Aubrieta, Purple Rock Cress · flowering

A vigorous, mat-forming perennial that smothers itself in rich purple flowers each spring. Ideal for walls, rockeries, and slopes, it cascades attractively over edges and thrives in alkaline, sharply drained soil in full sun. Trim back hard after flowering to keep it compact and encourage a possible second flush.

Growth habit: Prostrate, mat-forming perennial; spreading and cascading

What fertiliser cascade purple aubrieta actually wants — and why

Cascade Purple Aubrieta 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 cascade purple aubrieta: 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 cascade purple aubrieta, 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 cascade purple aubrieta:

The dormant-season rule matters more than the exact interval: skip feeding entirely when cascade purple aubrieta 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 cascade purple aubrieta

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

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

Signs you are over-feeding cascade purple aubrieta

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

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 cascade purple aubrieta

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 cascade purple aubrieta care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

Flush cascade purple aubrieta 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 cascade purple aubrieta

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 cascade purple aubrieta — frequently asked questions

What fertiliser does cascade purple aubrieta 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. Cascade Purple Aubrieta 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 cascade purple aubrieta?

Apply a balanced granular fertiliser (e.g. 10-10-10) once in early spring as growth resumes. Avoid high-nitrogen feeds which promote lush foliage at the expense of flowers. A light top-dressing of garden lime every two to three years benefits plants on acidic soils. Apply a balanced granular fertiliser (e.g. 10-10-10) once in early spring as growth resumes. Avoid high-nitrogen feeds which promote lush foliage at the expense of flowers. A light top-dressing of garden lime every two to three years benefits plants on acidic soils. 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 cascade purple aubrieta?

What does over-feeding cascade purple aubrieta 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 cascade purple aubrieta 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 cascade purple aubrieta?