If you’re growing rhubarb then you can divide old crowns once they go dormant. This’ll be over the next few weeks as the weather turns cold. It’s easy to do and you’ll get more rhubarb in the future.
First, wait for your rhubarb plants to go dormant. This is likely to happen in November/December – the leaves will have all died off and you’ll just see a crown of buds peeping above the soil. On a day when the ground is soft (not on a frosty morning!) carefully dig up the crown and lift it out of the soil.
Use a spade (a nice sharp one!) to cut vertically through the root ball of the crown dividing it into sections. Each section needs to have a bud so that it can regrow.
Plant each of the new sections in the soil adding plenty of well rotted manure. You should leave 90cm between plants and make sure that the bud is just peeping out of the soil when you fill them in.
That’s it! Add a mulch if you like and wait until spring.