June is when roses should be at their best. The buds are swelling, the first blooms are opening, and the garden finally starts to feel like summer.
But it's also the time many gardeners spot an all-too-familiar problem: aphids clustering around the soft new growth.
These tiny insects are often green or pink, and they tend to gather on the youngest, most tender parts of the plant. You'll usually see them first on fresh shoots, unopened buds and the undersides of young leaves, where they feed on sap and quickly build up in numbers, according to the Royal Horticultural Society.
How to deal with aphids on roses safely
According to the Royal Horticultural Society, rose aphids leave behind a sticky residue known as honeydew, which can encourage black sooty mould, a dark film across leaves and stems. The RHS says sooty moulds don't attack the plant directly, but their growth is unsightly and can reduce plant vigour by preventing photosynthesis.
The RHS advises gardeners to "check roses frequently from spring onwards so action can be taken before a damaging population has developed" and to "use finger and thumb to squash aphid colonies where practical." In many gardens, aphid numbers drop once predator populations catch up.
Check for beneficial insects first
If ladybird or hoverfly larvae are already working through the aphids, let them. The RHS is clear that gardeners should "encourage aphid predators in the garden, such as ladybirds, ground beetles, hoverflies, parasitoid wasps and earwigs", so spraying too broadly can harm exactly the wildlife doing the job for you.
The £1 home remedy you can try now
If you have a visible cluster spoiling the buds, some gardeners turn to a simple kitchen-cupboard fix: a very weak solution of washing-up liquid and water.
How much washing-up liquid to use
BBC Gardeners' World Magazine advises: "As a guide, use half a teaspoon of washing up liquid diluted in a litre of water, and apply using a clean hand pressure sprayer. Try it on just one or two plants first and wait several days to observe the results before further use."
Gardeners should use caution when trying homemade sprays. Washing-up liquid is a detergent rather than a product designed for plant leaves, and stronger mixtures may increase the risk of damaging foliage.
Where to spray the aphids on roses
Aim only at the visible clusters: buds, shoot tips and leaf undersides. Don't soak the whole bush, and avoid open flowers where possible.
Avoid strong sunlight when using insecticidal soap, as it can scorch foliage and flowers. Spray later in the day if needed, and leave it alone during hot, dry spells when leaves are already under stress.
Test before treating the whole plant
Test the solution on a small area before treating the whole plant. Wait a few days and look for yellowing, browning or scorch marks. If you spot any of that, don't continue. Don't assume one spray has sorted it.
Insecticidal soap works on soft-bodied insects such as aphids. Still, homemade sprays carry a risk of plant damage and can also harm beneficial insects such as ladybird and lacewing larvae.
Used carefully, a diluted washing-up liquid solution can knock back visible aphid clusters, but it should be treated as a cautious spot treatment rather than a cure-all.
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