The presence of ants on a plant can often be a sign of a sizeable aphid colony, it has been suggested.
Sector commentator Helen Yemm makes her comments in the online pages of the Telegraph in response to a query from a horticultural enthusiast.
Ms Yemm suggests that the ants will be milking secretions from the aphids, noting that this occurs on plants such as roses and viburnums.
She states that if the gardener examines the unopened flower buds on the foliage – as well as at the tips of new shoots – they may be able to spot them at work.
In terms of taking steps to remove the pesky pests, Ms Yemm notes that they can be brushed off, but that newly hatched ones will return in a matter of days so this should be done on a regular basis.
"A more long-lasting solution would be spray them with a more powerful insecticide that acts by both direct contact and systemic action," she concludes.
The Royal Horticultural Society lists ladybirds, lacewing larvae and parasitic wasps as predators of aphids.