- Suited to all conditions except extreme cold, agapanthus start flowering in mid-spring and continue until winter.
- Little maintenance is required once a plant is established.
- It can be grown as a fire-retardant plant, and its thick roots can help reduce erosion.
- Some varieties do not seed — a common complaint with agapanthus.
Agapanthus praecox subsp. orientalis
Plant type: Perennial
Speak to a bush regenerator on Victoria’s Mornington Peninsula or in the Blue Mountains of New South Wales, or even to a ranger looking after some parts of New Zealand’s South Island, and you’ll hear agapanthus called an invasive weed. Gardeners and nurserymen, however, tell a different story. For them, agapanthus is a tough, beautiful, long-flowering plant.
One passionate friend and champion of agapanthus is David Glenn, who runs perennial specialist nursery Lambley Nursery at Ascot in Victoria. David grows many agapanthus cultivars which, he says, begin flowering in mid-spring and continue to do so until the frosts arrive. In David’s garden, agapanthus is a tough plant well suited to Australian conditions. It needs little extra water once established, is low maintenance and makes a flamboyant statement.
There’s an agapanthus for just about every garden niche, as the cultivars available now range in size from tiny plants to edge a border or path, to giant, strappy-leafed clumps that look striking planted around a swimming pool or ranged along a driveway.
Agapanthus (Agapanthus praecox subsp. orientalis) is a perennial that comes to cultivation from South Africa. It is grown in gardens everywhere, with cold the plant’s main limiting feature. Evergreen varieties tolerate mild frost but are damaged by temperatures below –5C. Even so, they will often regrow.
In cold climates, particularly where snow or frost are part of the winter scene, David recommends growing herbaceous agapanthus. These selections die down over winter to avoid the cold but re-shoot in spring. In cold areas, evergreen agapanthus are often grown in pots and kept in a sheltered spot over winter.
The agapanthus is designed for survival, from its thick, fleshy roots to luxuriant, strappy leaves. Its often long-lasting and bird-attracting flowers are held proudly on thick stems.
Agapanthus is susceptible to heat damage in extreme summers, especially when heatwaves push temperatures over 45C. It is more likely to be burnt by heat if the plant is already drought-stressed. Although its foliage and flowers are damaged by high temperatures, it does recover, sending out new growth when conditions improve.
Agapanthus can also be grown as a fire-retardant plant. While it does burn in a fire, it can help slow a fire’s progress and plants recover quickly after the blaze. To use agapanthus as a firebreak, plant thickly, without organic mulch, as a border to lawn or under deciduous trees. The thick roots also bind soil and can reduce erosion on steep or exposed slopes.
Agapanthus is useful to tie a garden together and lends itself to mass planting as a border. Who hasn’t seen a row of agapanthus along a driveway or fence and not admired them? As they put on their best flower show in summer, they make a smart choice around outdoor entertaining areas and pools.
Smaller varieties can form a striking contrast to formal clipped hedges. Use a row of dwarf white agapanthus in front of a stepped hedge of gardenias, murrayas or lilly pillies for year-round interest.
Agapanthus is propagated in two ways — by seed or by division of the clump. Where it has spread as what some call a weed, it is usually due to unwanted plants left in bushland areas. Once established, agapanthus can spread slowly by seed. Unlike berry-producing weedy plants, such as privet or cotoneaster, agapanthus is not spread by birds. Instead, seeds fall around the clump and have a tendency to drift downhill.
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. But with a sharp pair of secateurs and wheelie bin or other container close by, it’s a job that doesn’t take long.
As well as removing the spent heads to prevent weediness, it also tidies the clump, returning lush agapanthus to their neat and orderly appearance.
If you are selecting new varieties to plant in your garden, consider some of the sterile or near-sterile varieties that are now available. David Glenn especially recommends three blue agapanthus to gardeners. The midnight blue ‘Guilfoyle’, the long-flowering, pale blue ‘Perpetual Peace’ and the delicate pale blue ‘Pallidus’ are varieties that produce few viable seeds.
Indeed, ‘Pallidus’, an old variety originally developed in Holland, was thought to have been lost to cultivation. It was rediscovered in Australia and David has since donated plants to the national agapanthus collection in the Netherlands (Nederlandse Planten Collecties).
The plant produces stiff stems 90cm tall with large heads of the palest blue flowers, and David has planted it to line his driveway. He says one of the joys of his driveway planting of ‘Pallidus’ is to watch the flocks of New Holland honeyeaters that visit the flowers over summer. The stout rather than arching stems of this variety readily support the birds’ weight. He enjoys the spectacle when this delightful cultivar is in bloom, from November until February.
For other weed-free options, consider ‘Snowstorm’ and ‘Snowball’, two low-growing, white varieties, and the dark blue ‘Black Pantha’, an elegant choice that has tall heads of deep blue blooms. The ‘Black Pantha’ flower heads stand 1.5m high and bloom right through summer.
Traditionally, agapanthus come with either blue or white flowers but current breeding is turning that on its head. With every shade of blue from the palest to dark-almost-black tones, agapanthus is now also available in bicoloured blue and white, as well as plants with pinkish flowers sold as ‘Roseus’. One bicolour variety now available is ‘Queen Mum’ with blue and white flowers that set few seeds. It grows to 1.5m high and 75cm wide.
These varieties produce few, if any, viable seeds so do not become weedy.
- One of the darkest blue agapanthus available, ‘Black Pantha’ flowers over summer. Its large stems can reach 1.5m and it has no viable seed.
- The dense, dark blue blooms on ‘Guilfoyle’ are held well above the leaves for six to eight weeks. It grows 1.5m tall and reaches 80cm across.
- ‘Pallidus’ has light blue flowers and is an old Dutch variety admired for its extended flowering season, from November to February. It grows 90cm high and wide.
- Bi-coloured plants such as ‘Queen Mum’ are new forms on the Australian market and a must-have for agapanthus fanciers. ‘Queen Mum’ is ideal as a garden border.