Growli
Let's go

Fertilising guide

How to fertilise Black-eyed Susan 'Goldsturm' (Rudbeckia fulgida)— schedule & NPK

Also called Black-eyed Susan, Goldsturm Coneflower, Orange Coneflower.

More about black-eyed susan 'goldsturm'

About Black-eyed Susan 'Goldsturm'

Rudbeckia fulgida · also called Black-eyed Susan, Goldsturm Coneflower · flowering

Black-eyed Susan 'Goldsturm' is one of the most reliable garden perennials, producing an incredibly prolific display of deep golden-yellow daisies with dark chocolate-brown central cones from midsummer to autumn. It is drought-tolerant once established and attracts pollinators and birds. Mildly toxic to pets.

Growth habit: Upright clump-forming herbaceous perennial

What fertiliser black-eyed susan 'goldsturm' actually wants — and why

Black-eyed Susan 'Goldsturm' flowers best on poor soil — feed it and you get a lush leafy plant with very few blooms, the exact opposite of what you want.

Little or nothing. Rich, especially nitrogen-rich, soil pushes foliage at the expense of flowers in this plant — lean ground is the technique, not a deficiency.

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 black-eyed susan 'goldsturm': 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 black-eyed susan 'goldsturm', 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 black-eyed susan 'goldsturm':

Apply a balanced slow-release granular fertiliser in early spring. Avoid heavy nitrogen feeds which cause excessive leafy growth at the expense of flowers. In fertile garden soils, no additional feeding is typically necessary. In practice: no routine feeding at all for black-eyed susan 'goldsturm' — at most a thin compost mulch for soil structure, never a flowering or nitrogen feed.

The dormant-season rule matters more than the exact interval: skip feeding entirely when black-eyed susan 'goldsturm' 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 black-eyed susan 'goldsturm'

None is the correct answer for black-eyed susan 'goldsturm'. The flower-versus-foliage trade-off is the whole point: hold back and you get the display.

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

Signs you are over-feeding black-eyed susan 'goldsturm'

Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for black-eyed susan 'goldsturm':

Signs you are under-feeding black-eyed susan 'goldsturm'

If the symptoms point at watering, light or roots rather than nutrition, the full black-eyed susan 'goldsturm' care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

If black-eyed susan 'goldsturm' has accidentally been fed and is all leaf, a plain-water flush plus a move to leaner soil resets it; otherwise no flushing is needed because you are not feeding it.

Organic vs synthetic feeds for black-eyed susan 'goldsturm'

Organic options

A thin compost mulch for soil structure is the absolute most; mostly, give it nothing. UK/US: leave it lean — no manure, no liquid feed. Poor soil is the active ingredient here.

Synthetic / liquid feeds

None. Synthetic feeds, particularly anything with appreciable nitrogen, directly suppress flowering in black-eyed susan 'goldsturm'.

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 black-eyed susan 'goldsturm' — frequently asked questions

What fertiliser does black-eyed susan 'goldsturm' need?

Little or nothing. Rich, especially nitrogen-rich, soil pushes foliage at the expense of flowers in this plant — lean ground is the technique, not a deficiency. Black-eyed Susan 'Goldsturm' flowers best on poor soil — feed it and you get a lush leafy plant with very few blooms, the exact opposite of what you want.

How often should I feed black-eyed susan 'goldsturm'?

Apply a balanced slow-release granular fertiliser in early spring. Avoid heavy nitrogen feeds which cause excessive leafy growth at the expense of flowers. In fertile garden soils, no additional feeding is typically necessary. Apply a balanced slow-release granular fertiliser in early spring. Avoid heavy nitrogen feeds which cause excessive leafy growth at the expense of flowers. In fertile garden soils, no additional feeding is typically necessary. In practice: no routine feeding at all for black-eyed susan 'goldsturm' — at most a thin compost mulch for soil structure, never a flowering or nitrogen feed.

What strength of feed for black-eyed susan 'goldsturm'?

None is the correct answer for black-eyed susan 'goldsturm'. The flower-versus-foliage trade-off is the whole point: hold back and you get the display.

What does over-feeding black-eyed susan 'goldsturm' look like?

Abundant leafy growth and very few flowers (the classic over-rich symptom). Soft, floppy stems and a sprawling, leafy habit. Scorched edges and salt crust if it has been fed in a container. Feeding black-eyed susan 'goldsturm' at all — especially "to help it flower" — is the defining mistake. Rich soil gives you a big green plant and almost no blooms; restraint is what produces the flowers.

Should I flush the soil of black-eyed susan 'goldsturm'?

If black-eyed susan 'goldsturm' has accidentally been fed and is all leaf, a plain-water flush plus a move to leaner soil resets it; otherwise no flushing is needed because you are not feeding it.

Keep reading