1. Use Insecticidal Soap
Insecticidal soap is a gentle but effective treatment that breaks down the aphids’ outer layer, killing them without harming most beneficial insects.
How to apply: You can buy insecticidal soap from most garden centres, or make your own by mixing 1 tablespoon of mild dish soap (unscented) with 1 litre of water. Spray directly onto the aphids, ensuring good coverage on all sides of the leaves and stems.
Tip: Spray early in the morning or late in the day to avoid leaf burn, and repeat every few days if needed.
2. Try Neem Oil or White Oil
Neem oil is a natural pesticide that also acts as a mild fungicide, helping prevent black spot and powdery mildew on roses.
How to apply: Mix according to the label’s instructions and spray evenly over affected plants. White oil (a blend of vegetable oil and soap) works similarly by suffocating soft-bodied pests.
Tip: Avoid spraying during hot afternoons. Early morning or early evening is best.
3. Release Beneficial Insects Like Ladybirds
Ladybirds (ladybugs) are natural predators of aphids and can eat dozens per day.
Where to get them: Some NZ suppliers offer live ladybirds online or at garden centres. Release them near infested plants at dusk so they’re more likely to stay.
Tip: Avoid using pesticides for a few days before and after release to avoid harming your helpers.
4. Make a Garlic and Chilli Spray
This DIY remedy deters aphids without harming your plants.
How to make it: Blend 2–3 garlic cloves, one small chilli or a teaspoon of chilli flakes, and 1 litre of water. Let it steep for a few hours, strain, and spray on affected plants.
Tip: Test on a small section first to ensure your plants don’t react badly. Reapply after rain.
5. Prune Affected Growth
If aphids are concentrated in one area, pruning can quickly reduce numbers and stop them from spreading.
Tip: Always disinfect pruning tools between cuts to avoid spreading disease, especially on roses.
6. Try Companion Planting
Certain plants naturally deter aphids — and can enhance the look of your garden.
Plant these nearby: Marigolds, garlic, chives, and lavender all work well in rose gardens and also attract beneficial insects.
7. Use Pyrethrin-Based Spray (As a Last Resort)
If other methods fail, a pyrethrin-based insecticide can knock down large infestations.
Use with care: Pyrethrins are derived from chrysanthemum flowers and break down quickly in sunlight, but they can still harm bees and other beneficial insects. Apply in the evening, and only to affected areas.
Final Thoughts
Managing aphids doesn’t have to mean reaching for harsh chemicals. With the right approach, you can keep your roses healthy using natural, safe methods — many of which you can make or apply yourself.
If you’re unsure which method to use, or the problem keeps returning, feel free to get in touch. We can assess your garden and recommend the best course of action for your plants and conditions.