A very popular plant in the south of France. Indeed a little further south than here in the Mediterranean area they almost grow like weeds and I am always very jealous of gardeners in this area. But for those of us who live in areas with frosts it is still possible to grow agapanthus.
If your soil is very wet it is better to grow them in pots and shelter them in winter. Otherwise give them a deep mulch to protect them from the worst of the frosts and remove this in the spring when they start growing again.
Agapanthus are commonly known as African lilies and come in various shades of blue and purple and also white. Different varieties have different sized flower heads and range in size of the overall plant.
The cultivar 'Back in Black' is particularly attractive as its dark blue flower sits on a virtually black stem.
The Agapanthus 'Headbourne Hybrids' are some of the most frost resistant and so if frost is a problem where you live these are a good choice. The Headbourne Hybrids vary from pale to dark blue and flower from July to September.
Agapanthus remain attractive even after flowering as the flowers are replaced by dark seed pods which have a strong architectural look.
Agapanthus are very attractive set amongst the grey leaves of many Mediterranean plants but I think one of the best combinations I have seen recently was in one of the outside beds at the Eden Project. Here there was a long border of orange cannas with bronze leaves and in front of this a mass of deep blue agapanthus. Magic!!
Agapanthus should be grown in rich well drained soil. It is useful to give them an application of a general fertiliser in spring. If you find your agapanthus are not flowering as you hope it could be that they need to be divided. Generally they need dividing every four to six years. Another possible reason is that they need to be grown in a sunny spot, indeed I think this was the problem with my pots of Agapanthus this year as I kept them on my north-facing patio throughout summer and autumn. They are now sheltering for winter but I am going to put them out next to a west facing wall in the spring.
Make sure you keep your pots watered in autumn as this is when the buds form and drought at this time of the year can cause the buds to die. During the spring and summer water regularly but not too much and feed with tomato fertilizer every two weeks.
Note that the roots of agapanthus can cause skin irritations and so always wear gloves when dividing or potting your plants.