October and November are perfect months to divide rhubarb clumps as they become dormant before the winter
I remember the early days of my career which involved looking after a National Collection of rhubarb and wondering whether it was the most visually unstimulating collection that was possible to grow. These days, as I grow a more sensible amount of rhubarb, I have come to appreciate how tasty and incredibly useful this plant is. There are very few fruits or vegetables that will tolerate a shaded position in a veg patch or container, but rhubarb ticks that box with gusto. October and November are perfect months to divide rhubarb clumps as they become dormant before the winter.
It is advisable to lift and divide your rhubarb every three or four years to maintain a good level of vigour while reducing the tendency for the clump to produce flowers too. Rhubarb roots are thick and woody, with very few fibrous roots, so don’t be alarmed if your rhubarb roots are more akin to tree roots. The centre of the crown will also be very woody and will require some gentle prising from the ground.
To lift, insert your spade around the clump, giving 20cm clearance from the edge of the clump to ensure that you lift as much of the root system as possible. Begin to lift the clump by undercutting with a more diagonal action, coupled with gentle lifting, until the clump becomes free. I tend to use a piece of tarpaulin to slide the rhubarb onto, which makes it easier to transport to its new site, while retaining the soil around the roots which will protect those finer and more delicate parts of the root system.
If your rhubarb clump is around, say, 45cm wide, it is possible to divide that clump into two or three pieces. Use a sharp spade to cut through the clump, ensuring that there is an adequate amount of root and two or three buds to form a new clump. With any division, you need a root and a shoot at the very least!