What is ‘dividing’?
‘Dividing’ is the act of digging up a plant and splitting it into several new plants to replant in your garden.
Why do we divide plants?
We divide plants for a few reasons:
- To reinvigorate them so they are healthier and produce more flowers
- To create more plants for free
- To ease congestion if the plant has become too big and overgrown.
Many perennials will respond well to being divided and will be healthier and happier plants for it. Dividing plants can seem and look quite brutal but don’t be scared of doing it. Your plants will thank you for it!
You will find that perennials that are a few years old can become quite big and overgrown if left to grow unchecked. Dividing them every few years keeps their health and vigour in tip top condition meaning healthier plants all round and more flowers.
An extra bonus is that you get more plants for free which can be replanted in your garden or shared with friends and family.
When do you divide plants?
Summer flowering perennials can be divided in either spring or autumn when the soil is warmer and wetter. Spring flowering perennials can be split in autumn and autumn flowering perennials can be done either in late autumn after flowering has finished or in spring.
What plants should I be dividing?
Any perennial can be divided, including grasses, but a few examples are:
- Echinacea
- Aster
- Geranium
- Salvia
- Nepeta
- Agapanthus
- Hosta
- Canna
What tools will I need?
Depending on what plant you are splitting you may find you need different tools, but usually you will need a border spade and fork, secateurs, trowel and a watering can.
How do I divide my perennials?
Dividing perennials is super easy as long as you have the tools required.
Some plants such as Hostas will need to have a circle cut around the plant about 10-20cm from the crown and then you can use your spade or border fork to get underneath the crown and ease the plant out of the ground. You can then use your spade to slice through the crown to make as many new plants as you like. You just need to make sure that each piece of your plant has at least one bud or new shoot on it and then you can replant them.
Other perennials may be easier to get out of the ground and will only need your border fork to get underneath the plant to ease it out, but otherwise the process is the same. In some cases the plants can just be teased apart with your fingers and will not need a spade to split them.
You will find some perennials such as Nepeta and Geranium will consist of lots of small plantlets which can be teased apart without the need of a spade or fork and can be replanted singly or you can clump a few together and replant them like that.
How should I be replanting my divided perennials?
Re-planting your divided perennials is exactly the same process as putting a new plant in the ground. You may want to put a slow release fertiliser in the planting hole to give the plants a boost after dividing. You can also trim the roots slightly if there are a lot of long roots attached to the plant. This will spur the plant into producing new roots which will help it to establish quicker.
How do I look after my plants once I’ve divided them and replanted them?
The only other attention your divided perennials will need is watering. Once you have replanted them they will need a good soak and will need watering regularly if the weather is dry. You will need to do this for several weeks until they have established in the ground and can find their own water.
How often should I be dividing my plants?
In general you should only need to be dividing your perennials every 2-3 years.
The Do’s and Don’ts of dividing perennials
Do divide your perennials every 2-3 years
Do divide your perennials in Spring or Autumn preferably when the soil is warm and wet
Do split your plants into a few good sized pieces
Do make sure each new plant has one new bud or shoot on it
Do use a spade to cut through tough crowns such as Hostas
Do trim the roots to promote new root growth
Do feed your new divisions with a slow release fertiliser such as osmocote
Do water your newly planted divisions regularly
Do share your newly divided perennials with friends and family if you wish
Don’t divide your plants while they are in bud or flower
Don’t divide your plants in winter when the ground is cold or frozen
Don’t divide your plants in mid summer when the ground is hot and dry
Don’t leave your new plants without water in dry or hot weather
Don’t divide your plants into tiny pieces. Good sized pieces gives them a better chance of thriving.
Don’t forget to feed your divisions. Dividing can be a shock for the plant so feeding them on replanting will give them a boost.
Don’t divide your perennials if they are too small to split.