Fertilising guide
How to fertilise guelder rose (Viburnum opulus)— schedule & NPK
Also called guelder rose, European cranberrybush, cramp bark.
More about guelder rose
About guelder rose
Viburnum opulus · also called guelder rose, European cranberrybush · flowering
Guelder rose is a vigorous native European shrub bearing lacecap white flowers in late spring, followed by brilliant red translucent berries in autumn alongside vivid red and orange foliage. Fully hardy to USDA Zone 3, it thrives in moist soils and part shade, making it an outstanding wildlife and woodland garden shrub.
Growth habit: Large, multi-stemmed deciduous shrub with a rounded, spreading habit; vigorous and suckering; outstanding for autumn colour and wildlife value.
Watch for — Viburnum leaf beetle (Pyrrhalta viburni): Larvae skeletonise leaves from inside the rolled leaf in spring; adults feed on foliage in summer. Viburnum opulus is highly susceptible. Check leaf undersides for egg cases in autumn and crush them; remove infested stem tips in spring before larvae hatch.
What fertiliser guelder rose actually wants — and why
guelder rose 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 guelder rose: 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 guelder rose, 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 guelder rose:
Generally undemanding in fertile garden soils. Apply a general-purpose balanced fertiliser or well-rotted garden compost in early spring. Over-feeding produces lush leafy growth at the expense of flowers and berries; avoid high-nitrogen fertilisers. In practice: no routine feeding at all for guelder rose — 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 guelder rose 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 guelder rose
None is the correct answer for guelder rose. 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 guelder rose first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the guelder rose watering schedule.
Signs you are over-feeding guelder rose
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for guelder rose:
- 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.
Signs you are under-feeding guelder rose
- Effectively never an issue — these plants flower on poverty.
- Only on genuinely dead soil: weak, thin growth and few blooms.
- A short-lived plant in completely spent container compost.
If the symptoms point at watering, light or roots rather than nutrition, the full guelder rose care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
If guelder rose 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 guelder rose
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 guelder rose.
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 guelder rose — frequently asked questions
What fertiliser does guelder rose 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. guelder rose 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 guelder rose?
Generally undemanding in fertile garden soils. Apply a general-purpose balanced fertiliser or well-rotted garden compost in early spring. Over-feeding produces lush leafy growth at the expense of flowers and berries; avoid high-nitrogen fertilisers. Generally undemanding in fertile garden soils. Apply a general-purpose balanced fertiliser or well-rotted garden compost in early spring. Over-feeding produces lush leafy growth at the expense of flowers and berries; avoid high-nitrogen fertilisers. In practice: no routine feeding at all for guelder rose — at most a thin compost mulch for soil structure, never a flowering or nitrogen feed.
What strength of feed for guelder rose?
None is the correct answer for guelder rose. The flower-versus-foliage trade-off is the whole point: hold back and you get the display.
What does over-feeding guelder rose 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 guelder rose 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 guelder rose?
If guelder rose 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
- guelder rose care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water guelder rose — 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 congo cockatoo impatiens
- How to fertilise oliver's impatiens
- How to fertilise wild pansy
- All 6887 fertilising guides in the Growli library