Plant of the month – agapanthus

These blue and white stalwarts of summer displays give week upon week of colour. But how can you get the most out of them?

women looking at agapanthusI would be surprised if you were to not find agapanthus growing now in most large gardens and estates across the country. In my mind, they have become a stalwart of a summer display, fitting beautifully into most garden styles and borders, especially if you are looking to introduce blues and whites into your summer scheme.

Here at RHS Garden Hyde Hall, its splendour can be enjoyed in our beautiful mixed herbaceous and shrub border on Clover Hill, as well as our Dry Garden and Farmhouse Garden. It also is a great seller at our flower show each August.

Agapanthus SylviaCultivation

As with all plants, the key to growing agapanthus is knowing a little about where it comes from and what it likes. They originate in South Africa, which is why it is often been referred to as the ‘African lily’. There are two main types; those that are deciduous and those that are evergreen. The deciduous types are hardier than the evergreen ones, and prefer to be dry over the winter.

The key to growing agapanthus successfully is making sure they receive full sun (they will not perform well in the shade). They also like fertile, well-drained soil that keeps the moisture. Here at Hyde Hall we sit on heavy clay, but by enriching the soil with compost and grit, we have been able to create the perfect soil moisture balance. 


Although agapanthus can be grown from seed, the best way to propagate plants is through division. Divide after flowering and up until September. Try to avoid dividing the plants into clumps that are too small as this will reduce the amount of flower stems you can enjoy. The best way I have found is to bring your clumps on for a few years and then divide.

Agapanthus with gall midge damagePest and diseases

Until recently, agapanthus had few pest and disease problems, the main issues being frost or virus damage. However since 2014, the plant has been affected by a gall midge, which affects the flowers (see photo).The RHS science team has launched a project to study it, working with Defra and international experts. The Royal Horticultural Society would be happy to receive samples of infested flowerheads in 2016. Please send any samples in sealed bags or containers to:

Entomology, RHS Garden Wisley, Woking, Surrey, GU23 6QB

Alternatively images (with postcode) will contribute to the UK distribution mapping and can be sent to: [email protected]

As the agapanthus is such a beautiful plant I would hope that this should not deter a grower from putting such wonderful plants into their garden. It truly is special.

Salvia patensMore about perennials

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