Agapanthus are a real showstopper and thrive both in plant pots and beds. We can give you the right plant and care tips.
The Agapanthus genus encompasses ten species which include both summer and evergreen representatives. The botanical genus name Agapanthus is derived from the Greek words ‘agape’ (= love) and ‘anthos’ (= flower), which is why the Agapanthus are also called ‘Flower of Love’. Shrubs belonging to the Allioideae family (Alliaceae) originate from South Africa, where they grow in open grassland and rocky areas. While the evergreen species in South Africa are widespread in mild, coastal regions, the deciduous types grow in cooler regions in the country and are therefore somewhat more frost-tolerant.
The species Agapanthus praecox subsp. orientalis is widespread in the gardens of South Africa in particular. The evergreen Agapanthus praecox is also one of the best known species, although there are now also numerous other varieties available. The species Agapanthus africanus (evergreen) and Agapanthus campanulatus (deciduous) are also popular in western Europe. While evergreen species only thrive in tubs in cooler climates and must overwinter indoors, deciduous species, in particular the Headbourne hybrids, can be readily planted in flower beds in milder regions.
Appearance and Growth
With their relaxed blue-violet or white, bell-shaped flowers, Agapanthus flowers with their rounded, terminal flower head position on long stems above the foliage are a beautiful eye-catcher from July to August in flower pots or flower beds. However, the green foliage with its smooth, arch overhanging leaves are also a beautiful sight. The individual, strappy leaves can be between 3.94 and 40 inches long, depending on the species and variety. In addition to the green-foliage species, there are also varieties with striped or white margined foliage. The growth height varies between 12 and 70 inches.
Location and Substrate
Agapanthus thrive in a sunny, sheltered space, although they do still bloom well in semi-shade. In tub planting, the plant pot should be filled with around a 3.9 inch deep drainage layer of or gravel to prevent the fleshy roots from rotting. Fill the rest of the plant pot with tub plant soil. Evergreen Agapanthus are suitable for balconies and terraces or also cold and temperate conservatories, deciduous species thrive in nutrient-rich, permeable soils, and in flower beds. When planting in pots, ensure that the plant pot is only a little larger than the root ball, as flowering is less intensive in oversized flower pots. This is also why Agapanthus should only be re-potted when the old plant pot has become much too small.
The tub plants require a lot of watering, in particular during the flowering period. Ensure that no water remains in the plant saucer. Agapanthus also require a lot of nutrients. So they should be fed a high-quality, liquid tub plant fertilizer once a month from April to August. But they should not be fertilized more frequently as it is widely accepted that: Agapanthus bloom best when they are slightly undernourished. If they are over-fertilized then they do form a rich foliage, however only a few flowers, if any.
Agapanthus do not generally require pruning. Simply deadhead the entire stem. This not only makes them more visually appealing, it also promotes the formation of new flowers and further ensures that the Agapanthus do not cross breed with one another.
Evergreen agapanthus need to be brought into a light winter habitat with temperatures between 41 to 45 degrees Fahrenheit before the first frost. If the temperature is too warm, they form fewer flower buds, and if it is too dark, the foliage will turn yellow. They require minimal watering: just enough to prevent the soil drying out. They can be taken outside again after the last late frosts in April/May. Planted deciduous species should be protected during the first year in particular with some fall foliage or bark mulch.
Agapanthus are generally propagated through division. The best period for this is during the months of March and April, even if, in principle, plants can be divided all year round. For Agapanthus cultivated in tubs, un-pot the intended agapanthus and divide the thick root ball with a sharp spade or knife. There should not be too long a gap between un-potting and replanting the divided pieces, as the roots may not dry out. That’s why, when the divided plants have been re-potted, the first thing they need is a good drink. Afterwards, they only require occasional, light watering until they have formed the first leaves. They can then be well-watered up to flowering. The flowers will be somewhat sparser in the first year after dividing.
Dividing is particularly recommended for plants and hybrids which have become to large. You can also propagate agapanthus with seeds, however agapanthus species cross breed very easily with one another and propagation through seeds rarely leads to the offspring looking the same as the mother plant.
Species and Varieties
From a gardening perspective, only three of the ten species are interesting: the deciduous Agapanthus campanulatus and the evergreen Agapanthus praecox and africanus. There are also numerous recommended hybrids available commercially. Take particular care when purchasing to determine whether the varieties are evergreen or deciduous, as this characteristic has a significant influence on the winter-hardiness.
The varieties ‘Albus’ and ‘White Heaven’, for example, are captivating with their pretty white flowers. While the former is deciduous and therefore can also be be planted in flower beds with light winter protection, the latter is mainly suited for a plant pot garden. ‘White Heaven’ also reaches a growth height of up to 40 inches, somewhat higher than ‘Albus’ which only reaches a height of approximately 30 inches.
If you prefer the classic violet and blue flower colors, you can take your pick of the bunch, as there are numerous varieties here, some of which however, vary only slightly in flower color. The deciduous, blue flowering hybrid ‘Headbourne’ is an extremely robust and frost-resistant example. The deciduous ‘Midnight Dream’ has pretty, dark violet-blue which also look great planted in contrast to the white-flowering agapanthus due to their dark colored flowers. The variety ‘Blue Giant’ is a classic among the agapanthus. It forms dark blue bell flowers which grow up to 47 inches high.
Diseases and Pests
Agapanthus are robust and have hardly any problems with plant diseases or pests. Occasionally, individual flowers fall foul to aphids. Agapanthus also react sensitively to waterlogging. Therefore, ensure there is good drainage in plants planted in a tub.
Frequently asked questions
What kind of soil is suitable for Agapanthus?
Agapanthus are happy with high-quality tub planting soil. Incidentally: A ten centimeter high drainage layer made up of gravel or expanded clay should be planned in when planting.
How often should Agapanthus be watered?
Agapanthus must be regularly watered, particularly when flowering. However, care should be taken to avoid waterlogging.
How should Agapanthus be fertilized?
Agapanthus is an extremely hungry plant and should be fertilized approximately once a month from April to August. You should use a high-quality liquid tub fertilizer for this.
When do Agapanthus flower?
Agapanthus flower from July to August.
When should Agapanthus be deadheaded?
As soon as the flower dies the stems can be removed. This promotes flower formation.
Agapanthus: What are the ideal overwintering conditions for Agapanthus?
Agapanthus which are kept in a pot should be brought in before the first frost. The ideal winter residence is light and between 41 to 45 degrees Fahrenheit. Agapanthus which have been planted out are best protected with a layer of bark mulch or some autumn leaves.
When can Agapanthus be put outside?
Agapanthus can be taken outside again at the end of April/start of May.