Perennials to plant now

I want to add some herbaceous perennials to gaps in my garden. Which are best planted in the autumn, and which should I leave until spring? Alice O'Connor, Keighley, W. Yorkshire

A Plugging gaps is a great idea to shade the soil, protect it from moisture loss and prevent weeds. But best of all, you'll have flowers in borders and for vases. A permanent backbone of woody shrubs and trees will stay in place for many years, but although also potentially long-lived, herbaceous perennials are a moveable feast.

A few herbaceous perennials are evergreen or semi-evergreen, and some have slightly woody bases, but in the main these versatile plants die back for winter and grow again in the spring.

They are easy to lift and move around, usually when dormant, and during the process larger clumps are often divided into smaller portions. This benefits the plants, rejuvenating their growth and flowering, as well as making more of your favourites. If and when gaps between shrubs begin to close over, you can simply lift your herbaceous perennials and move them somewhere else. Some devote whole borders or even gardens to these durable plants.