How and when should I feed roses?

Roses are among the hungriest plants in a British garden, particularly repeat-flowering varieties, which are asked to produce several complete sets of flowers in a season. That said, feeding is a supporting job, not a fix: a rose that is not flowering because of shade, wrong-time pruning or replant disease will not be rescued by fertiliser, and heavy nitrogen makes several rose problems worse.

Step by step

1. Feed first in early spring, as the buds break.Roughly March in most of the UK, when the leaf buds are visibly swelling and starting to open. A granular rose fertiliser scattered over the root area — which extends at least as far as the plant is wide — and lightly forked or watered in.
2. Mulch straight after the spring feed.A 50 to 75mm layer of garden compost or well-rotted manure over damp soil, kept a hand's width clear of the stems. It feeds slowly, holds moisture through the summer, and covers black spot spores lying on the soil surface.
3. Feed again after the first flush finishes.Usually late June into July. This is the feed that powers the second and third flushes on a repeat-flowering rose, and it is the one most often forgotten.
4. Stop feeding by early August.Late nitrogen pushes out soft new growth that has no time to ripen before the first frosts, and soft unripened wood is exactly what dies back over winter and lets canker in. This deadline matters more than the exact products used.
5. Use a rose or general fertiliser rather than a lawn one.Rose fertilisers are formulated with enough potash to support flowering. Lawn feeds are nitrogen-dominant and produce a large leafy rose with very few flowers.
6. Water before and after feeding in dry weather.Granular fertiliser on bone-dry soil does nothing and can scorch surface roots. Water the ground, apply the feed, water again.
7. Use a liquid high-potash feed for roses in pots.Container roses exhaust their compost in about six weeks and cannot send roots out to find more. A weekly liquid feed through the growing season, plus fresh compost or top-dressing each spring, is the regime that keeps them going.
8. Do not feed a newly planted rose in its first spring.Concentrate on water. A bare-root rose planted in winter has all the nutrients it needs in the soil around it and needs to grow roots outward, which heavy feeding discourages. Start the normal routine in its second year.

Tips

• Epsom salts are only worth applying if you actually have a magnesium deficiency, which shows as yellowing between the veins on older leaves while the veins stay green. Applying it routinely does nothing useful.
• Banana skins under a rose are a garden tradition rather than a feeding strategy. They contain some potassium but release it far too slowly and in far too small a quantity to matter.
• Roses growing at the foot of a wall are usually short of water before they are short of food. Check that first.
• Well-rotted manure is the traditional rose mulch for a reason — it feeds and conditions at once. Make sure it is genuinely well rotted; fresh manure scorches.

Common mistakes

• Feeding a shaded, sulking rose harder — Light, not food, is the limiting factor. Extra nitrogen produces more soft leafy growth in poor light, which increases disease and reduces flowering further.
• Feeding into September to get one more flush — The soft growth it produces is killed by the first hard frost and becomes an entry point for canker and dieback.
• Letting lawn feed drift into a rose bed — It is one of the commonest causes of a rose that grows vigorously and flowers badly. Keep the spreader well away from borders.

If it doesn't work

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