Can ants floating in water damage flowers?

Garden Experts

Dear Mr Kötter, my summerhouse has gutters that channel rainwater into a water butt. Our tap water is very hard so I like to use rainwater for my herbs in particular. A few days ago, I noticed that there were about two or three hundred ants swimming on the surface of my water butt. They were clinging onto each other, probably out of desperation, and struggling not to go under. The rain must have swept them off the roof of the summerhouse and into the water butt. But what should I do now? When I take water from the butt, I pour ants directly onto my herbs and other plants — will this damage the flowers? Could you give me some advice? Thank you in advance for your help and best wishes from sunny Baden-Württemberg.

The GARDENA gardening expert

Your assumption that the ants were washed off the roof is probably right. It is worth checking that it really was the runoff that swept the ants down the gutters and into the water butt. This then begs the question of why the ants were on the roof or in the gutters in the first place and where their nest(s) might be. I received your question in mid-April, just when these insects become more active — for instance, climbing up plant stems to establish colonies of aphids on them (for "milking"). So why would they be scaling your summerhouse? Are they trying to reach host plants? For example, ants frequently "farm" aphids on elders. Or could it be that the ants have nested somewhere in your summerhouse, in the wall or under the roof for instance? If so, and if the ants are causing problems or could cause damage, it is probably best to call a pest controller. These suggestions should enable you to find a way of preventing more ants finding their way into your water butt.

Insects that land on your garden and plants with water from your butt will not do any harm. Dead ants become "fertiliser", and any surviving ants will simply die in your flowerbeds because they will be unable either to find the scent trail to lead them back to their nest or to start a new colony.