To keep perennial plants performing at their peak, it’s necessary to lift and divide most of them every few years. Both spring and autumn are good times to do this. You’ll end up with more plants than you started with, so begin a new flower bed or give the extras to a friend, local horticultural society or schools. As a last resort, the discards can go on the compost.

Many gardeners prefer to divide their crowded perennials in the fall. It is best to divide and replant allowing enough time to establish roots in the new location. Our rule of thumb: Allow four to six weeks in the new location before the first hard frost occurs in your area.

Dividing perennials in spring has it advantages. Plants have not leafed out, making it easier to dig around the root mass, the soil is moist from the winter snow melt and garden soil is cool, which helps to wake up perennials gradually.

How to divide perennials

Plants are usually divided for one or two reasons. Firstly, the plant has outgrown its given space, or it is fully mature and needs rejuvenating. This becomes noticeable when the centre of the plant begins to deteriorate. You might choose to move established plants in spring to make room for other plants as many perennials can become aggressive after a few years.

Identify the plants that are overgrown and dig them up using a garden fork. We like using a good quality garden fork as it damages fewer roots. If you only have a spade or shovel, that will work too. Sharpen digging tools with a grinder or use a gardener’s file.

Drive the fork into the ground around the entire plant, without moving the tynes; just slide them in and out of the soil as you cut through young feeding roots of the plant. After you have completed the circle one time without using leverage, do it again only this time push down on the fork/spade ripping and tearing roots as you go. You are permanently damaging the roots by doing this. The remaining root mass will grow new roots. By the time you have completed your second pass around the plant chances are pretty good it will lift easily out of the ground. Now lever the digging tool with your body weight. Many densely rooted perennials such as Hosta will “pop” when the roots are set free.

Take your time. Once you have the plant – roots and all – out of the ground, you have a decision: How many divisions will you make?

After dividing the plant in half, do it again, dividing it into quarters. If it is a really large plant, you can divide it again. Now you have a bunch of wedges sitting on the ground ready to plant. If you can’t plant them right away, place them in a shady spot and water them thoroughly. Keep them wet until you can plant them over the next few days or give them away.

When you plant your new divisions, use good quality soil (triple mix works nicely) and water them well.

What perennials are suitable for dividing?

• Mature plants
• Fibrous or fleshy roots systems
• Out-of-bloom and dormant

These plants are easily divided: Yarrow, astilbe, monarda (Bee Balm), bellflower, coreopsis, evening primrose, phlox, veronicas and the extremely popular Hosta.

It’s spring: Time to dig, divide, replant and revive your garden.