Horticulture Magazine

How to Grow Agapanthus in Pots

agapanthus growing in a large terracotta garden container

Agapanthus, also known as the African Lily, is a herbaceous perennial plant, prized for its attractive flowers which come in a range of blueish-purple hues, or in white.

Though this plant comes from South Africa, and loves sunshine and warmth, it can be grown outdoors in the UK with winter protection and an appropriate location and care.

Can You Grow Agapanthus in Pots?

three large containers with agapanthus plants of varying colours

Agapanthus can be grown in pots or other containers.

Indeed, this is a popular choice for UK gardeners, since it makes it easier for the plants to be moved to an undercover location in winter.

There are deciduous and evergreen agapanthus.

The deciduous type tend to be somewhat hardier, and some can cope with remaining outdoors year-round in a sheltered spot in more southern or coastal regions.

Evergreen types (and even hardier types in chillier and more northerly gardens) are almost always grown in containers so that they can be moved into an unheated greenhouse or other protected location over the winter months.

Choosing a Container

purple flowering agapanthus in a terracotta plant pot

Individual agapanthus plants are often grown as pot grown plants over the summer months.

But you may also decide to grow Agapanthus from bulbs, which are best planted in around April, after the last frost date in your area.

Single plants will usually be grown in a container which is around 20cm in diameter.

If your plant came in a pot, do not be too quick to repot it into a larger container than the one in which it came.

Restricting The Roots

an agapanthus plant removed from its pot with visible roots

Agapanthus actually likes its roots to be restricted, so take care to choose a container only slightly larger than the existing root system.

The exact size of container you should choose will of course depend on the specific variety, and the age and size of a plant (or plants) you have selected.

If you have purchased several smaller plants, these can be placed snugly into a larger container – as long as the root systems fit into the container, they should be happy in the restricted space.

Pots should be deep enough to allow the root systems to sit around 5cm below the surface of the growing medium, and so that there is around 5cm at the top, above the surface of the medium, where water can pool and soak in, and not run off.

In terms of materials, a terracotta pot can be ideal.

The colour complements the blooms of these plants and the porous material can make for good, free-draining growing conditions.

Make sure the container you choose also allows water to drain freely from the base.

Choosing Compost

agapanthus plant placed in a new white plastic container

The ideal growing medium for Agapanthus is a peat-free, loam-based compost or potting mix, such as John Innes number 2 or 3 (or a home-made equivalent) with grit or coarse sand mixed in to improve drainage.

Place your plant or plants into your chosen container, and fill in your chosen potting mix around the roots, taking care not to leave any air pockets.

Water well upon planting, then consider adding a decorative mulch across the top of the container to aid in moisture retention and keep things looking neat and attractive.

Potting Up Agapanthus

large blue flowering agapanthus in a huge planter

Remember, Agapanthus likes to have restricted roots, especially while young.

Your plants will not need to be repotted for the first couple of years at least.

After this, it may be beneficial to repot your plant or plants into slightly larger containers.

How Many Can You Plant Per Pot?

agapanthus plant hanging from a barrel plant pot

You can plant as many Agapanthus plants into a container as will comfortably fit without damage to the existing root systems.

The plants can sit snugly together without ‘complaint’ and should thrive even if things seem crowded.

If growing from bulbs, these should be spaced approximately their own width apart from one another, at least 5cm below the surface of the growing medium.

Caring For Agapanthus Plants in Containers

terracotta pots growing lavender and agapanthus with a wall in the background
  • Place an Agapanthus in a container in a sunny, warm and sheltered spot.
  • Water container grown Agapanthus a couple of times a week over the summer months.
  • Feed the plants with a potassium rich organic liquid plant feed (such as comfrey tea) every week or so during spring and summer for good flower development.
  • Deadhead flowers after a spectacular display over the summer.
  • Prune out any damaged or dead foliage in autumn.
  • For deciduous types (not evergreens), cut back stems to around 10cm above the ground at the end of autumn.
  • Move the container to a frost-free location such as an unheated greenhouse over the winter. (But do not move it anywhere too warm, as this can lead to poor growth and flowering the following year.)

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