Sudden wilting is almost certainly due to the vine weevil larvae (grubs) actively feeding on and destroying the plant’s root system. While adult vine weevils cause minor, notched damage to the leaves, it’s the C-shaped, creamy-white grubs with brown heads that live in the soil and are the true culprits. They effectively sever the plant from its vital roots, preventing it from taking up water and nutrients. This leads to symptoms mimicking underwatering, with the plant looking droopy and sad, even after being watered, and in severe cases, the entire plant can easily be lifted from the soil as there are no roots left to anchor it.

So, what can we do to protect our precious container plants from these subterranean munchers? Always check the rootball of any new plant you bring home for these grubs. A hands-on approach is often most effective in controlling them. Regularly inspecting your plants, particularly in the evening when the adult weevils are most active, allows you to directly intervene. Look for the tell-tale notched leaves, which are a sign of their feeding. Once spotted, carefully pick off the adult weevils and relocate them to prevent them from laying eggs in your containers. This method, while requiring vigilance and consistency, significantly reduces the number of damaging grubs in your container soil. Focusing your efforts on checking and picking is particularly crucial from spring through to late summer when the adults are most prevalent.

I do not recommend using biological controls, such as nematodes, because they can potentially infect other animals. They should be used with caution and only when there is a specific problem that needs to be addressed. By the time you realise you have these grubs, it may be too late to save the plant.

Losing a Heuchera or other plants to vine weevils is only a matter of time for many container gardeners in the UK. But by understanding the issue and taking preventative measures, we can stand a much better chance of keeping our colourful garden additions thriving.