Rose: lower leaves turning yellow

What it is likely to be on rose

1. Rose black spot

   Candidate 1very common on this plant

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Rose black spot

   Checked 2026-08-13

   Rounded black blotches with a diffuse fringed edge on rose leaves, usually with yellowing spreading out from them, followed by early leaf fall. It is specific to roses — the commonest fungal disease of the genus in Britain — and is not the explanation for a dark spot on anything else.

   Points towards it

   • · the yellowing spreads outward from dark blotches with ragged edges rather than arriving on its own
   • · the lowest leaves are infected first by spores splashing up from the soil
   • · the spores need several hours of leaf wetness to germinate, so a wet summer drives it
   • · an outdoor disease spread by rain splash

   Argues against it

   • · a marbled green-vein pattern with no blotches anywhere on the leaf is a magnesium shortage instead — this rules it out entirely.
   • · evenly yellow leaves with no dark marks on them are not black spot — this rules it out entirely.

   Check this next

   Hold a yellowing leaf flat and look at the edge of the dark marks on it. Black spot makes purple-black blotches with FEATHERY, irregular margins that bleed into the surrounding tissue, and the leaf yellows around them before it falls — round marks with clean edges are a different leaf spot, and yellowing with no marks at all is not a disease.

   What to do now

   Collect up and bin the fallen leaves rather than composting them, because that is where the fungus overwinters to reinfect next year. Prune to open the centre of the bush so the foliage dries quickly after rain, mulch in spring to stop splash from the soil, and choose varieties with recorded resistance when replacing a bush that suffers badly every year.

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Rose black spot — control

   Checked 2026-08-13

2. Magnesium deficiency

   Candidate 2common on this plant

   ·source

   Sourced guidancemoderate confidence

   • Royal Horticultural Society: Roses — feeding

   Checked 2026-08-13

   Yellowing between the veins of the OLDER, lower leaves while the veins themselves stay green. Magnesium is mobile within the plant, so it is withdrawn from old growth to supply new — which is exactly why the pattern starts at the bottom.

   Points towards it

   • · the tissue between the veins yellows while the vein network itself stays green
   • · the plant moves magnesium out of the lower leaves and into the flowering shoots above them
   • · high-potassium rose feeds compete with magnesium at the root and commonly bring this on part-way through the season

   Argues against it

   • · dark blotches on the leaf mean black spot is driving the yellowing, which needs a completely different response — this rules it out entirely.
   • · an evenly pale leaf including the veins is nitrogen rather than magnesium — this rules it out entirely.

   Check this next

   Check the leaf for dark blotches BEFORE reading anything into the yellow. On a rose the two causes look similar at a distance and want opposite responses: clean yellowing between green veins on the lower leaves of a bush with no spots on it is magnesium, commonly on a light soil and after a summer of rose feed — and Epsom salts will answer it where a fungicide would do nothing at all.

   What to do now

   Water in Epsom salts at about 20g per litre around the root zone in late spring, and mulch annually with well-rotted manure. On light soils magnesium leaches every winter, so an annual mulch does more for a rose than increasing the feed — and adding more high-potassium feed makes the shortage worse rather than better.

   ·source

   Sourced guidancemoderate confidence

   • Royal Horticultural Society: Magnesium deficiency — treatment

   Checked 2026-08-13

Narrow it down

This page lists everything at once, which is the right shape for reading and the wrong shape for deciding. The interactive tool asks one question at a time, starting with whichever would separate these causes fastest, and stops as soon as further answers would not help.

Opens with the plant and the symptom already set. Nothing you answer is stored or sent anywhere — the answers live in the address bar and nowhere else.

What this does not cover

These are the causes GrowingHQ holds rules for on rose — not every cause there is. Where several problems look alike, the honest answer is often that they cannot be told apart by eye, and a page that named one would be guessing. If none of the above fits, the general lower leaves turning yellow page lists causes across all plants, and the Rose profile lists the problems it is prone to.