If the plants appear yellow or growth is poor, they will benefit from being fed with a liquid fertiliser – a good choice would be Miracle-Gro All-Purpose Water-Soluble Plant Food. This is a great all-rounder and can be used for many other plants too.

Keep the plants deadheaded when flowers are finished and fading. This will keep them tidy and encourage a new flush. Dying stems can also damage the crown and roots if battered about by strong winds, so they will also benefit from being cut back too.

That’s not to say that all herbaceous plants should be cut back. Many gardeners like to leave some plants intact (especially those with attractive seedheads). They give added interest in winter and provide vital food and shelter for wildlife. They can be cut back in spring when the new growth is appearing at the base.