Rust
Disease · Commonly affects: leeks, garlic, roses, hollyhocks, snapdragons, fuchsias, runner beans, pear trees
Rust is a group of fungal diseases that produce coloured spore pustules on leaves and stems. It is common in damp UK gardens, especially where plants are crowded or foliage stays wet. Different rusts affect different hosts, but most reduce plant vigour and spoil appearance rather than immediately killing established plants.
How to identify it
Look for tiny raised pustules, usually 1-3 mm across, in orange, yellow, rusty brown or black. They commonly appear first on leaf undersides, with pale or yellow spots visible above. The pustules may rub off as coloured dust on fingers. Leeks can develop rows of orange spots, while roses and hollyhocks show scattered patches on leaves and stems. Badly affected leaves yellow, curl and fall early.
Damage
Rust reduces the green leaf area that plants use for growth. Leeks may make smaller stems, while flowering plants such as roses and hollyhocks become weakened and unsightly. Repeated infection can lead to early leaf drop and poorer flowering the following year. Spores spread readily in damp weather, so disease can build up quickly in closely planted groups.
Prevention
Give susceptible plants adequate spacing and prune or stake them so foliage dries quickly after rain. Water the soil rather than using overhead watering, preferably early in the day. Remove fallen infected leaves throughout the season and clear old foliage at the end of it. Avoid planting the same susceptible crop in the same spot each year. Choose resistant varieties where available and keep plants well watered during dry spells without waterlogging roots.
How to manage it
Remove affected leaves promptly, especially the first heavily spotted ones, and put them in household waste. For leeks, strip off only badly affected outer leaves so plants can continue growing. Improve airflow by weeding, thinning nearby plants or tying in sprawling stems. Avoid handling wet foliage, which can spread spores. Clear all affected debris after harvest or flowering, and do not save seed from severely infected plants.
Rust: frequently asked questions
How do I identify rust?
Look for tiny raised pustules, usually 1-3 mm across, in orange, yellow, rusty brown or black.
How do I prevent rust?
Give susceptible plants adequate spacing and prune or stake them so foliage dries quickly after rain.
How do I get rid of rust?
Remove affected leaves promptly, especially the first heavily spotted ones, and put them in household waste.
General guidance for UK home gardens and allotments, focused on prevention and non-chemical control. For a confirmed diagnosis, the RHS or a local garden centre can help. Page updated 19 Sep 2026.