Why should you lift and divide perennials plants?

Your garden can look great for the first few years after you’ve planted it.  But then certain plants can start to take over and bully the more delicate ones.  If you’re not careful you’ll be left with a few thugs and lose the variety and interest you started out with.  Alternatively, if some plants get overcrowded they will stop flowering and you’ll have a lot of foliage, but less colour.  So about three years after planting most herbaceous perennial plants (those plants without woody stems) need to be dug up (lifted) and divided (or split).  This will rejuvenate them and give you more flowers, while creating extra plants you can share with friends or move to other parts of your garden.

When should you lift and divide?

The best time to do this is when the plant is almost dormant; when it is not actively growing.  This is in the autumn or early spring.  As a general rule you should lift and divide spring flowering plants in the autumn and summer and autumn flowering plants in the spring ..

Lift in the autumn (October/November)

  • Iris
  • Epimedium
  • Bergenia
  • Early Hardy geraniums


Lift in the early spring (March)

  • Alchemilla mollis (Lady’s Mantle)
  • Summer flowering Hardy Geraniums
  • Astilbe
  • Astrantia
  • Sedum/Stonecrop
  • Rudbeckia
  • Phlox
  • Crocosmia

How to lift and divide

Overcrowded Iris clump

Overcrowded Iris clump

On the left above is an overcrowded clump of Iris in my garden.  To tackle it, I first cut back all the leaves (on the right) to show how it has a bare patch at the centre of the clump.  This is quite normal for Iris to do after a few years – but can lead to fewer flowers.

Lift and Divide Iris clump

Lift and Divide Iris clump

Using a digging spade I cut around the clump to a depth of about half the spade (15cm – 20cm) and then levered it out of the hole and put it on the path to divide it.  Using the spade I split it into 5 sections – each with at least one shoot and a clump of roots – see below.

Divided Iris clump

Divided Iris clump

I then filled the hole in my border with a mix of fresh compost and top soil with some slow release fertiliser pellets and trod it down to get a good, level surface to re-plant into.

UPLOADING 1 / 1 – Filling and firming planting area.png ATTACHMENT DETAILS Filling and firming planting area

Filling and firming planting area

Once the bed was prepared I return some of the divided clumps to the bed, making sure they were spaced out.

Re-planting Iris

Re-planting Iris

The last job is usually to water in the plants – but at this time of year I knew there’d soon be some rain to do that for me!

More Gardening Tips

If you’d like more gardening tips come along to my workshops in the spring

How to Garden – Evening Class

Grow Your Own Vegetables

Or book me for some 1-2-1 Advice.