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Growing Agapanthus – The beginner’s guide to planting and general care
Last Updated on January 21, 2020 by John
The agapanthus, colloquially referred to as the African Lily is a perennial that blossoms in the summer and provides glossy leaves with collections of funnel shaped blooms that are the perfect addition to any table centre.
These flowers come in blue and purple varieties but there are pink and grey varieties available to those looking for something unique. These bring a subtropical appearance that thrives in any sunny location in a garden or in pots on your patio or porch. There are of course other varieties and hybrids that you can cultivate if you are looking for specific characteristics.
These plants thrive and so many places that it is important to understand how you can properly plant them and grow them successfully so that you, too, can enjoy all of the beauty they have to offer.
- Common name: African Lily, African Blue Lily, Lily of the Nile
- Scientific name: Agapanthus Africanus
- Height: 50-150cm
- Light: Prefers full sun
- Hardiness: Most are hardy down to -10°C
- Soil: grows in rich, well-draining soil
- Propagation: Propagate by division
- Pests: resistant to most diseases and pests
- Maintenance level: easy
When you start planting in your garden you will need a mixed soil that’s very good quality with some compost and horticultural grit for improved drainage. In general, plants will flower more effectively if they are partially root constrained the first few years so they thrive in pots and they need this dryer mixture to recreate the same location where they originated.
In the garden, they also need good drainage. They need moisture retentive soil that is fertile. There are a few varieties that can grow in soil that isn’t well-draining as long as you add grit when you plant them. They will adapt to moderate pH levels except for the main agapanthus Africanus which needs acidic soil. If your growing them in pots use a compost such as John Innes No2 or No3 which is loam based.
Plant in a sunny spot in the garden
In terms of the light requirements, they need full sunlight, with 8 to 10 hours of sunshine throughout the summer. There are a few that can tolerate a handful of partial shade seasons during the summer but if you can find a spot that gets full sunlight use it as they tend to flower poorly when not grown in a sunny spot.
Watering & feeding
You won’t have to water much in the winter but your garden plants will need frequent watering in the spring and summer if there is a shortage of natural rainfall. You want to avoid too much water but of course, keep the soil moist. When it comes to growing them in pots they will need regular watering as they often become a little rootbound and don’t retain the moisture well.
When it comes to feeding your plant you want to use a nitrogen-based fertilizer and do it at the end of March and then every two weeks thereafter until the middle of September.
Pruning and splitting
In terms of pruning, you can cut away damaged leaves or dead leaves at the base any time of year. Otherwise, the evergreen varieties should not be pruned except for your annual maintenance. If you have a deciduous variety you can cut it back to approximately 10 centimetres off the ground once it is finished producing flowers at the beginning of autumn. If your plant is spreading beyond the space you have available you can remove large clumps that are growing together every 4 years and then split that clump into several separate pieces as a method of producing more plants from the original.
Growing agapanthus in pots
When you are growing in your pots you want to make sure there is proper drainage in the pot itself. In some cases, this might require you to drill additional holes in the bottom simply because come winter time if you live in a colder area the evergreens that you grow in pots are more prone to winter waterlogging so they need extra drainage.
When you grow agapanthus in a pot you can place a single plant in a pot that is approximately 30cm in diameter filled with a mixture of loam-based compost such as John Innes No3 and horticultural grit to help improve drainage. If you have younger plants you can place three of them in a single 50cm pot. In general, they seem to flower much better if the plants are partially root constrained in the pots so it’s good to keep them in the same pot for at least a few years before you transplant or divide them. If you are only going to keep one plant in a single pot, it is best to keep that pot no bigger than 30cm in diameter even at its full maturity. every few years when you notice it not doing as well you can then remove it from the pot divide and then replant again.
The soil that you use in the pot needs to be well draining with a moderate pH level so most loam-based compost falls under this. You should move the pot to a location before you transplant which gets at least 8 to 10 hours of sunlight. When you fill the large pots with compost and subsequently with your agapanthus, they will be very heavy so it’s best to move them to the location in your garden where you want them to remain before you do that.
If you are growing in pots you have to water much more frequently throughout the spring and the summer but you cannot allow the plant to be left in standing water. During the colder months between November and March you won’t really need to water much if at. You should move the pots however to a frost-free area such as an unheated greenhouse. You don’t want to move them to a warm area during the winter because that can restrict the number of flowers you get the following year but you do want to move them away from any damage they might incur due to harsh winds, snow, and frost.
The feeding regimen should be the same as that listed above for garden base plants.
A healthy plant is generally problem-free but one issue in colder winters is rhizome frost damage. Even the strongest of varieties can be susceptible to this at which point you will see the tips of the leaves yellowing which is suggestive of waterlogged conditions. If the leaves turned pale you might need to add supplementary feeding.
In terms of pests, one of the issues you might face is a red spider mite or mealybug. Both of these problems can be tackled by spraying the appropriate insecticide or organic alternative through the winter.
If you are growing your plants in pots you might notice a new issue where the flower buds are deformed or discoloured while the rest of the foliage is healthy. This can be indicative of the larvae of the gall midge inside your plants and if so it is recommended that you destroy the infested flower head or the entire plant. Any pots or containers need to be emptied with the roots and rhizomes properly cleaned and replanted in different containers moved to different locations to avoid overwintering larvae from manifesting later in the year. the container should not be used again for any agapanthus but it can be cleaned and used for other plants without issue.
There are many different varieties available all of which derive from the species that originated in South Africa. The deciduous plants that offer pale to rich blue colours come from the cooler climates in the Drakensberg mountains. Of course, there are some warmer climate varieties along the Western Cape of South Africa which can thrive in fairly acidic soils and maintain their foliage throughout the winter.
Agapanthus Africanus has deep blue colours and is found at sea level. Agapanthus Africanus walshii grows more in dryer warmer areas.
There are many species now that have been cultivated and readily available for gardens of all sizes. If you want a blue variety of flowers, Midnight Star is the best variety to choose. For a smaller location, the dwarf variety of Lilliput is ideal. Those looking to grow the white flowers would do well to select the Arctic star variety.
Displays of a beautiful lilac colour all summer long can be achieved with the headbourne hybrids. Other hybrids include the Brilliant Blue and midnight dream each of which provides the dark purple flowers. The Margaret variety gives a powder blue colour while the Twister variety offers blue and white flowers concurrently.
If you want a middle of the road blue flowers that have a dark purple stripe down the centre, the Northern Star variety is going to be perfect.
If you have a smaller garden and you need something more compact you can pick the white storm or blue storm which will flower for approximately 70 days in a row and are smaller by design.
If you have a colder garden that is less sheltered and fairly open, the agapanthus Africanus will thrive very effectively. Summer pots that you place outdoors should be filled with variety such as the Hole Park Blue, Lapis Luzuli, and Purple Delight.