Agapanthus pruning is also essential to encourage healthy growth. You can do this after the flowering season, cutting back the stems to around 10 cm above ground level for deciduous varieties, which include Agapanthus Melbourne, Agapanthus Galaxy White, and Agapanthus Little Galaxy.
Cut back the flower stems all the way to the base of the plant. Deadheading prevents the plant from going to seed and helps the plant store energy in the rhizome. If self-seeding is desired, allow a few blooms to produce seed and ripen on the stem.
Agapanthus are perennials which means they come back each year. Most are hardy, and their leaves will die back each winter before returning in the spring. Evergreen types tend to be more tender, so will need some protection in the winter and early spring.
It is a perennial plant that can live for up to 75 years. Its evergreen leaves are 2 cm wide and 50 cm long. Its inflorescence is an umbel. The flowers are blue, purple or white and bloom from late spring to summer, followed by capsules filled with black seeds.
Dividing and transplanting agapanthus
One advantage of growing agapanthus is that once you've got one, you're guaranteed to have more, because they multiply by themselves in clumps. However, if left untouched for any length of time, they will become overcrowded and may flower poorly.
Because agapanthus plants spread quickly, they are regarded as an invasive weed in parts of New South Wales and Victoria. Your local council can provide guidance on growing agapanthus, which may include dead-heading flowers before seed dispersal.
Repeat flowering Agapanthus for up to 6 months of the year.
These gorgeous plants produce masses of bright and colourful flowers in spring and summer, as well as sporadically throughout the year, including in mild winters as seen in 2020.
To restrict its spread from your garden, deadhead stalks as flowers finish and don't dump unwanted plants. If you have a mass planting of agapanthus, deadheading sounds onerous, particularly for a plant that's often grown for its low maintenance.
It's not too difficult. Dig up a clump, separate it into the desired number of divisions, and replant them back into other areas of the landscape or in pots. Dividing agapanthus does discourage blooming, and the smaller you make the divisions the longer it will take the plants to come back into bloom.
Deadheading agapanthus
When the flowers' colours have faded, you can deadhead them by cutting off the flower at the base of the stem. (Alternatively, you can leave the seedhead on the plant for some winter interest.)
Generally 3-4 inches deep for the larger variety and about 2 inches for the dwarf varieties.
Collect seed when the seedhead is becoming brown and the capsules are starting to burst. If the weather is turning cold you can collect seed prematurely and store the whole seedhead in a paper bag, but it's preferable to let the seed ripen on the plant.
Herbicide Sprays to Kill Agapanthus
Common recommendations are for glyphosate, metsulfuron-methyl (MSF600) and triclopyr (Triclo). Our experience is that they all will work, but that glyphosate and MSF600 are more effective at some times than at others.
Agapanthus grows and spreads by fleshy rhizomes that act as storage roots. The plant retains nutrients in its roots and may be divided to create more plants. Use a sharp shovel to dig up an established plant and divide it into several sections, each with roots and foliage.
Symptoms: Symptoms may include nausea vomiting, abdominal pain and diarrhoea if ingested, with severe ulceration of the mouth from the clear sticky sap. Skin contact with the sap may cause a burning sensation, skin irritation and rashes. Warning: Seek medical attention for all ingestions.
Agapanthus species should generally be kept cool over winter. The optimum temperature is between 0 °C and 5 °C. Excessively high temperatures lead to reduced flowering in the coming year. It is essential to overwinter evergreen species in a frost-free place.
With proper care, agapanthus flowering occurs repeatedly for several weeks throughout the season, then this perennial powerhouse returns to put on another show the next year.
Agapanthus needs extremely well-draining, but somewhat water retentive, soil to survive. This may be hard to achieve in your garden, which is why growing agapanthus in pots is such a good idea. Terra cotta pots look especially good with the blue flowers.
Agapanthus species are hardy plants, and are easily grown. Although tolerant of drought and poor soil, both flower and foliage production improves with moisture and feeding. They perform best in a position in full sun or part-shade in any well-drained soil.
Agapanthus
Agapanthus is so common in South Australia that the tall blue or white flowers are one of the sure signs of summer. Originating in South Africa, they are well adapted for our climate and multiply to form large clumps of broad, strappy leaves.