Last updated on March 3rd, 2022
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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 flowers that are the perfect addition to any table centrepiece.
These flowers come in varieties of blue and purple, however, there are pink and grey varieties available for those who are 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 decking. There are of course other varieties and hybrids that you can cultivate if you are looking for specific characteristics.
These plants thrive in so many locations, and 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 Agapanthus 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 a dry 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 that needs acidic soil. If you are growing them in pots use compost like 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 during the summer, however, if you can find a spot that gets full sunlight use it because they tend to flower poorly when not grown in a sunny spot.
Watering and Feeding
You won’t need to water that much in the winter, but your garden plants will need frequent watering in the spring and summer if there is a shortage of natural rain. 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 because they often become a little rootbound and don’t retain the moisture as well.
When it comes to feeding your plant you want to use a nitrogen-based fertiliser 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 or dead leaves at the base any time of year. Otherwise, the evergreen varieties shouldn’t be pruned except for your annual maintenance. If you have a deciduous variety you can cut them back to approximately 10cm off the ground once it has 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 (if you live in a colder area) the evergreens that you grow in pots are more prone to winter waterlogging so will require extra drainage.
When you grow an 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 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 and then every few years, when you notice it isn’t doing as well, you can then remove them 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 and most loam-based compost falls into this category. You should move the pot to a location before you transplant that it gets at least 8-10 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 will need to water much more frequently throughout the spring and the summer and you shouldn’t 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 all. You should move the pots, however, to a frost-free location, 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 and you want to move them away from any damage they might incur due to harsh winds, snow and frost.
The feeding regime should be the same as the method we have written about above for Agapanthus that have been planted in the flowerbeds.
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 different problem, 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 the larvae that will allow them to manifest 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 any 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 of the Drakensberg mountains. Of course, there are some warmer climate varieties along the Western Cape of South Africa that 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 dry and warmer areas.
There are many species now that have been cultivated and are readily available for gardens of all sizes. If you want a blue variety of flowers, ‘Midnight Star’ is the best variety to choose and 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’ that 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 varieties such as the ‘Hole Park Blue’, ‘Lapis Luzuli’ and ‘Purple Delight’.