Agapanthus Regal Beauty, a new planting by the Temple of Arethusa (and by the Campanile) at Kew Gardens. I missed photographing them the last visit (damned batteries!) but they are still in fine fettle. I was not the only one stopping to admire these gorgeous creatures.
How to grow: Agapanthus
We show you how to grow agapanthus – a beautiful and increasingly popular plant
Bold and architectural, agapanthus are strikingly beautiful plants that have become very popular in recent years. Originating in South Africa, and often called African lilies, their strappy leaves and statuesque stems, topped with balls of intensely coloured flowers, fit easily into a modern garden setting or a traditional mixed border. They also make fantastic specimen plants for pots, yet their glamorous looks are surprisingly low maintenance and there are many that will survive the winter outdoors.
There are two main types of agapanthus – deciduous and evergreen – and the surge of interest in them has led to the breeding and introduction of hundreds of new varieties. So which ones should you grow? Nineteen varieties were tested by Which? Gardening magazine, and four were outstanding. For the full trial results and more choice varieties, see the July/August issue of Which? Gardening.
The trial
The agapanthus trial took Best Buy varieties from the last trial in 1997, along with recommendations from specialist nurseries and National Collection holders, including a range of the more recent varieties.
The plants were grown outside without winter protection, starting in spring 2009, with three plants of each variety grown at two trial sites: Capel Manor Gardens in north London, where the soil is well-drained and summer rainfall is often light; and Bishop Burton College in Yorkshire, where the soil and rainfall are heavier, and winters generally colder.
Plants were watered until established, but then only watered if they showed signs of stress from drought. In the first winter, once the plants had begun to die down, a 2-4in layer of green-waste mulch was applied to protect them from the worst of the cold. This was removed from the crowns of the plants as they started to grow in the spring.
The harsh winter of 2009-10 certainly tested their hardiness. The plants were assessed weekly throughout the growing season for both their development and their attractiveness.
Top four performers
All four plants below survived at both trial sites and flowered well in the North and South alike. They also had the longest flowering seasons of all those on test and were rated highly by assessors for appearance.
Agapanthus ‘Northern Star’
A classic agapanthus with clumps of short strappy leaves and cobalt-blue flowers with a prominent darker stripe in the middle. The tall stems tended to be a bit floppy, but they were favourites at both trial sites all the same. A deciduous type, ‘Northern Star’ flowered for six weeks from July to August and reached a height and spread of 35x28in.
Agapanthus inapertus ‘Midnight Cascade’
Indigo tubular flowers droop from the heads, topping elegant stems in a way typical of the lovely inapertus type. The deep purple colour was much admired by visitors to the trial sites. A deciduous type, it flowers for six weeks from August to September and achieves a height and spread of 28x24in.
Agapanthus ‘Headbourne Hybrids’
This is one of the best-known agapanthus varieties. ‘Headbourne Hybrids’ didn’t disappoint, giving a fabulous display of lilac-blue flower heads. A deciduous type, with a flowering time of five weeks, from July to August, it reaches a height and spread of 28x30in.
Agapanthus ‘Peter Pan’
A compact evergreen agapanthus with sparser flower heads than many varieties but lots of flower stems, which give plenty of impact. This variety’s neat shape would suit the front of a border or a container. An evergreen type, it flowers for five weeks from July to August. Attains a height and spread of 20x24in.
Growing tips
The deciduous agapanthus species come from colder regions and are generally hardier. The evergreen species are from milder parts of South Africa which have higher rainfall. These varieties tend to be less hardy and may not remain evergreen if the winter is very cold.
All agapanthus are drought tolerant and a good choice for coastal areas, coping well with wind and salty air.
Plant in well-drained soil and in full sun.
It may take two or three years for plants to establish before flowering really takes off.
Mulch in autumn or cover the crown of the plant with straw or fleece to protect from cold. Even deciduous varieties can benefit from this practice.
If clumps become too big, they can be lifted and split every four to five years.
If planting in a pot, move it to a sheltered spot in winter so that the roots don’t freeze.
Plants flower well in pots if the roots are constricted. However, they should be split and replanted in fresh compost if the roots become too congested, otherwise flowering will suffer.
Agapanthus combine well with other sun-lovers. A few suggestions include: Achillea millefolium ‘Rose Madder’, Coreopsis verticillata ‘Moonbeam’, Crocosmia x crocosmiiflora ‘Emily McKenzie’, Hemerocallis ‘Janice Brown’, Kniphofia ‘Little Maid’ and Stipa tenuissima.
The Teddington Gardener 