How to grow Agapanthus
Agapanthus are just great garden flowers, exotic looking, striking blue and coming to their peak in late July & August.
Like so many of our garden favourites, when growing Agapanthus, the trick is to get the right plant in the right place and this is very much the case with Agapanthus. The are about 10 species of Agapanthus both deciduous and evergreen, but most importantly, Agapanthus vary in hardiness. As a rule of thumb, the deciduous varieties are more hardy than the evergreen, and all varieties benefit from a good winter mulch.
When growing Agapanthus outside, if your garden is not sheltered, you will need to select a fully hardy variety, *** hardy, such as Blue giant, Midnight blue, Lilliput (as you may expect a short variety up to 10cms) Snowy Owl with white flowers. Check when you buy as selecting a hardy variety is the first important step to growing Agapanthus. For an explanation of what is meant by hardy follow this link
If your garden is exposed and prone to frost, or you wish to grow a more tender variety, Agapanthus grow very well in pots and can easily be moved into a unheated conservatory or greenhouse for the winter. If you live in Cornwall, or the Scily Isle you can ignore this advise as Agapanthus grow everywhere flowering freely in the mild conditions.
Even though Agapanthus like moisture retentive soil, perversely they will establish in containers, and all Agapanthus like sun as they originate from warm climates in South Africa. Agapanthus do well in coastal gardens, being tolerant of salty winds, and positively thrive in Cornwall and Scillies, where they seem to grow wild. For more ideas about coastal gardens follow this link. Growing Agapanthus is very rewarding with their striking flowers and foliage, and easier to grow in milder areas of the country where they can be left undistributed in the garden and will reward with many flowers year after year. Even in more exposed areas, by chosing a hardier variety and either mulching or growing in a container, Agapanthus can be grown all over the UK.
In some areas, Agapanthus can be tricky to get them to flower each year. The Agapanthus I had growing in the ground just sulked and added very little to the border. Reluctant to throw away such expensive plants, I dug them up and potted on into large containers and two years later, the flowers finally put in an appearance. Recently I have also read the advice of Quentin Stark from Hole Park gardens, who knows a thing about growing Agapanthus, who suggests if Agapanthus are not flowering in pots to replant in the ground, and visa versa. It seems to work, Stark also suggests don't molly coddle or overfeed which is gardening advice I always like; least is best.
If your Agapanthus will not flower in the ground, in the summer with lots of plant foliage for cover, place the pots in the borders to add colour and dig out and sink the container into the bed. I have seen this done with both Agapanthus and Dahlias to good effect, which are then easy to lift to store/overwinter elsewhere.
How to look after Agapanthus in the winter
Looking after Agapanthus in the winter depends on both the variety you are growing, and your garden aspect. Many Agapanthus are described as hardy and they do grow better in the south, and no surprise how well they grow in Cornwall and the Scillies but in many areas they will benefit from some protection in winter. It is necessary to check the precise variety you are growing, but as a general rule the deciduous varieties are more hardy than the evergreen types. The RHS new hardy ratings take into account other aspects apart from a simple temperature reading, as aspect is also important; some plants maybe described as hardy but if the ground is wet may not survive the winter.
Agapanthus when planted in most gardens, apart from very mild areas, will benefit from a winter mulch of around 15-20 cms of straw or similar, I find strulch very good. As the evergreen varieties are more tender they may need a fleece during the worst of the winter cold. If your garden is very exposed it is best to move the Agapanthus to a more sheltered spot or into the greenhouse for the winter which unless you like digging, it is best to grow Agapanthus in pots. In all sheltered areas the more hardy varieties of Agapanthus will be fine with a mulch. In more exposed gardens, and if growing some of the evergreen more tender varieties, Agapanthus will need a fleece or to be in an unheated greenhouse. The Agapanthus in the image above spends winter in the greenhouse and flowers very well. The main causes of Agapanthus failing to flower are too much shade, Agapanthus are sun loving, and dislike cold temperatures and lack of winter protection .