Dividing Agapanthus – How and when to divide step by step

Last updated on March 2nd, 2022

Agapanthus are very versatile plants, especially in the summer and you can plant them in large numbers (in beds or pots) to create stunning borders. They require very little maintenance and they actually enjoy being a little crowded. If left to their own devices they will happily multiply into natural clumps of individual plants, however, they do benefit from being divided around every 4-6 years to keep them prolifically flowering.

Why you need to divide Agapanthus

If you noticed that the clumps of Agapanthus you have in your garden have started to get too big, they dominate the area and are preventing other plants from getting the nutrients they need, whilst at the same time also producing fewer flowers (which are most people’s concerns when it comes to growing Agapanthus) what should you do?

Divide and conquer. Or more specifically divide and split up the plants. The bonus here is that when you divide your plants you get additional plants you can put somewhere else or there’s always a friend who will happily take them from you if you don’t have room.

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When to divide Agapanthus

Evergreen varieties

The best time to divide your Agapanthus is in the spring or early summer as soon as you notice the new shoots emerging or alternatively in the autumn. We would personally recommend the middle of September or October once your plants have finished flowering.

While you’re making your decision about when to divide your Agapanthus, remember that if you divide them in the spring you are probably going to receive fewer flowers that year because you have disturbed the roots, however, they will benefit from it and produce a much better show the following year.

You should divide your Agapanthus plants every 4 to 6 years, or every time they begin to get too large and underproduce in terms of flowers. If you are growing them in pots they are more likely to stop flowering, so as soon as you see this happening it’s time to divide and replant in well-drained quality compost.

Deciduous varieties

The best time to divide your deciduous Agapanthus is in the spring or early summer as soon as the new growth begins to emerge, or at the end of autumn when the leaves have died back. You should only really divide deciduous varieties every 7 years, but again, look for signs of overcrowding and fewer flowers, and then split when the plants are ready.

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How to divide Agapanthus

In order to divide your Agapanthus you will need the following:

• Two large garden forks to pull apart the large clumps.
• A large spade (that is very sharp) to split the plants.
• A large knife or saw to split them into sections.

When you are ready, start by digging around each clump using your spade. If you have large clumps of Agapanthus, and more than one clump has become intertwined (which is usually the case when they are grown in the ground) you may need to slice directly through the roots on all sides by holding your spade vertically and cutting straight down.

Once that is done, lift the clumps out of the ground using your garden fork and be as precise as possible. These roots are very strong so it will take a great deal of effort for you to lift them, no matter how strong you are. Once they have been lifted, shake them to remove as much of the excess soil as possible.

At this point, you can split the clumps in half using your hands (if you are able to) but this is often a little difficult. If the roots are too far intertwined and you’re unable to do it by hand, then we recommend, if you can, place your two garden forks in the centre, back to back, and use one as a lever to force them apart. This makes the job much easier.

At this point, you should separate each clump into a smaller clump and each still with a healthy root system. You want to tease out the roots with your fingers or with the sharpened saw. You can split your clumps in half, break them down into thirds, quarters, or even cut them into individual parts, Agapanthus are very tough and will cope with this very well. The only thing to remember is that the smaller the cut sections of Agapanthus, the longer it will take for each plant to produce flowers once it has been replanted so we recommend keeping them as good sized divisions and none too small.

Now you want to trim the leaves back by approximately half or two thirds of the original size and trim away any damaged or long roots, this is so that the plants can concentrate on producing new roots and getting themselves established once replanted.

Before you replant them add rich well-drained compost to the soil to help the plants recover. Space each clump approximately 30-50cm apart if you are using larger clumps, however, if you are using individual plants space them approximately 10-15cm apart. When you put them in the ground spread the roots out and plant them at the same depth as they were planted originally because planting them too deep can rot the crowns.

Fill in the soil around the area and pat it down. Water it well so that any air pockets are alleviated, and make sure the plant remains moist for the following few weeks after it has been planted so that it has an opportunity to establish itself successfully.

We recommend that you split and plant straight away to minimise stress on the plants, however, if you are unable to transplant immediately, put the plants somewhere cool and cover them with a damp newspaper until such a time they can be transplanted.

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Last update on 2025-03-05 / Affiliate links / Images from Amazon Product Advertising API