Why has my plant stopped flowering?

A plant that has stopped flowering is usually perfectly healthy. Flowering is expensive, and the plant has decided it has better uses for the energy.

Step by step

1. Look at the leaves before anything else.Plenty of large green leaves and no flowers is the classic nitrogen picture. The plant is being fed to grow foliage and doing exactly that.
2. Switch to a high-potash feed.Tomato feed is the cheap and universal answer. Potash — the K in the NPK figures — drives flower and fruit production, where nitrogen drives leaves.
3. Stop general-purpose and lawn feeds nearby.Both are nitrogen-heavy, and lawn feed drifting into a border is a common and invisible cause of a bed that has gone leafy.
4. Count the hours of direct sun.Most flowering plants need six hours or more. Shade tolerance usually means the plant survives, not that it blooms. Nearby growth that has thickened over a few years is a frequent cause.
5. Check when it flowers on which wood.Many shrubs flower on last year's growth. Pruning in autumn or spring removes every flower bud, and the plant then grows strongly and blooms nothing. This is the commonest avoidable cause.
6. Prune immediately after flowering instead.For anything that flowers on old wood, cut back within a few weeks of the flowers finishing. That gives a full season to make next year's buds.
7. Deadhead through the season.Once a plant sets seed it has done its job and stops. Removing spent flowers before they seed keeps many annuals and repeat-flowering perennials going for weeks longer.
8. Consider whether it is too comfortable.Some plants flower better under mild stress — slightly pot-bound, slightly lean soil. Repotting a plant into something much larger frequently produces a year of leaves.
9. Check the plant's age and cycle.Some perennials and shrubs take years to reach flowering size, some flower biennially, and some fruit trees crop heavily one year and rest the next. Nothing is wrong in any of those cases.
10. Look for frost damage to buds.A late frost can kill an entire year's flower buds on magnolia, camellia and fruit trees while leaving the plant looking perfectly healthy.
11. Check the day length requirement.Poinsettia, Christmas cactus and chrysanthemum need genuinely long dark nights to set buds. Indoors, a lamp or a street light through a window is enough to prevent it.
12. Make sure watering is steady.Drought at the point of bud formation makes plants drop buds to survive. Irregular watering causes more bud drop than consistent moderate watering ever does.
13. Give it a full season after changing something.Most of these fixes affect next year's flowers rather than this year's. Judging in three weeks tells you nothing.

Tips

• Lots of leaves and no flowers means nitrogen. Tomato feed is the standard fix and it is cheap.
• Find out whether it flowers on old or new wood before you prune anything. It explains most non-flowering shrubs.
• Deadhead before it sets seed. Once seed forms, most plants stop.

Common mistakes

• Feeding a non-flowering plant more general fertiliser — General feeds are nitrogen-heavy, so the plant produces still more foliage and still fewer flowers. It needs potash instead.
• Tidying shrubs in autumn or early spring — Anything that flowers on last year's wood has its buds cut off, so it grows vigorously and flowers nothing. Prune after flowering instead.

If it doesn't work

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